diff --git a/crates/oxc_ast/src/ast/js.rs b/crates/oxc_ast/src/ast/js.rs
index d18389f538439..51bbfe7be7ba8 100644
--- a/crates/oxc_ast/src/ast/js.rs
+++ b/crates/oxc_ast/src/ast/js.rs
@@ -2281,6 +2281,8 @@ pub struct AccessorProperty<'a> {
     pub computed: bool,
     /// Property was declared with a `static` modifier
     pub r#static: bool,
+    /// Property has a `!` after its key.
+    pub definite: bool,
     /// Type annotation on the property.
     ///
     /// Will only ever be [`Some`] for TypeScript files.
diff --git a/crates/oxc_ast/src/generated/assert_layouts.rs b/crates/oxc_ast/src/generated/assert_layouts.rs
index e689ef636c567..84f15539af469 100644
--- a/crates/oxc_ast/src/generated/assert_layouts.rs
+++ b/crates/oxc_ast/src/generated/assert_layouts.rs
@@ -696,6 +696,7 @@ const _: () = {
     assert!(offset_of!(AccessorProperty, value) == 64usize);
     assert!(offset_of!(AccessorProperty, computed) == 80usize);
     assert!(offset_of!(AccessorProperty, r#static) == 81usize);
+    assert!(offset_of!(AccessorProperty, definite) == 82usize);
     assert!(offset_of!(AccessorProperty, type_annotation) == 88usize);
 
     assert!(size_of::<ImportExpression>() == 56usize);
@@ -2101,6 +2102,7 @@ const _: () = {
     assert!(offset_of!(AccessorProperty, value) == 36usize);
     assert!(offset_of!(AccessorProperty, computed) == 44usize);
     assert!(offset_of!(AccessorProperty, r#static) == 45usize);
+    assert!(offset_of!(AccessorProperty, definite) == 46usize);
     assert!(offset_of!(AccessorProperty, type_annotation) == 48usize);
 
     assert!(size_of::<ImportExpression>() == 32usize);
diff --git a/crates/oxc_ast/src/generated/ast_builder.rs b/crates/oxc_ast/src/generated/ast_builder.rs
index 6b5c325ea0cb2..d0962c38617cb 100644
--- a/crates/oxc_ast/src/generated/ast_builder.rs
+++ b/crates/oxc_ast/src/generated/ast_builder.rs
@@ -6496,6 +6496,7 @@ impl<'a> AstBuilder<'a> {
     /// - value: Initialized value in the declaration, if present.
     /// - computed: Property was declared with a computed key
     /// - r#static: Property was declared with a `static` modifier
+    /// - definite: Property has a `!` after its key.
     /// - type_annotation: Type annotation on the property.
     #[inline]
     pub fn class_element_accessor_property<T1>(
@@ -6507,6 +6508,7 @@ impl<'a> AstBuilder<'a> {
         value: Option<Expression<'a>>,
         computed: bool,
         r#static: bool,
+        definite: bool,
         type_annotation: T1,
     ) -> ClassElement<'a>
     where
@@ -6520,6 +6522,7 @@ impl<'a> AstBuilder<'a> {
             value,
             computed,
             r#static,
+            definite,
             type_annotation,
         )))
     }
@@ -7071,6 +7074,7 @@ impl<'a> AstBuilder<'a> {
     /// - value: Initialized value in the declaration, if present.
     /// - computed: Property was declared with a computed key
     /// - r#static: Property was declared with a `static` modifier
+    /// - definite: Property has a `!` after its key.
     /// - type_annotation: Type annotation on the property.
     #[inline]
     pub fn accessor_property<T1>(
@@ -7082,6 +7086,7 @@ impl<'a> AstBuilder<'a> {
         value: Option<Expression<'a>>,
         computed: bool,
         r#static: bool,
+        definite: bool,
         type_annotation: T1,
     ) -> AccessorProperty<'a>
     where
@@ -7095,6 +7100,7 @@ impl<'a> AstBuilder<'a> {
             value,
             computed,
             r#static,
+            definite,
             type_annotation: type_annotation.into_in(self.allocator),
         }
     }
@@ -7111,6 +7117,7 @@ impl<'a> AstBuilder<'a> {
     /// - value: Initialized value in the declaration, if present.
     /// - computed: Property was declared with a computed key
     /// - r#static: Property was declared with a `static` modifier
+    /// - definite: Property has a `!` after its key.
     /// - type_annotation: Type annotation on the property.
     #[inline]
     pub fn alloc_accessor_property<T1>(
@@ -7122,6 +7129,7 @@ impl<'a> AstBuilder<'a> {
         value: Option<Expression<'a>>,
         computed: bool,
         r#static: bool,
+        definite: bool,
         type_annotation: T1,
     ) -> Box<'a, AccessorProperty<'a>>
     where
@@ -7136,6 +7144,7 @@ impl<'a> AstBuilder<'a> {
                 value,
                 computed,
                 r#static,
+                definite,
                 type_annotation,
             ),
             self.allocator,
diff --git a/crates/oxc_ast/src/generated/derive_clone_in.rs b/crates/oxc_ast/src/generated/derive_clone_in.rs
index fc5b279277869..8d50ea3135b93 100644
--- a/crates/oxc_ast/src/generated/derive_clone_in.rs
+++ b/crates/oxc_ast/src/generated/derive_clone_in.rs
@@ -1954,6 +1954,7 @@ impl<'old_alloc, 'new_alloc> CloneIn<'new_alloc> for AccessorProperty<'old_alloc
             value: self.value.clone_in(allocator),
             computed: self.computed.clone_in(allocator),
             r#static: self.r#static.clone_in(allocator),
+            definite: self.definite.clone_in(allocator),
             type_annotation: self.type_annotation.clone_in(allocator),
         }
     }
diff --git a/crates/oxc_isolated_declarations/src/class.rs b/crates/oxc_isolated_declarations/src/class.rs
index 58bffaa898afd..4f60e524a6a55 100644
--- a/crates/oxc_isolated_declarations/src/class.rs
+++ b/crates/oxc_isolated_declarations/src/class.rs
@@ -469,6 +469,7 @@ impl<'a> IsolatedDeclarations<'a> {
                         None,
                         property.computed,
                         property.r#static,
+                        property.definite,
                         // SAFETY: `ast.copy` is unsound! We need to fix.
                         unsafe { self.ast.copy(&property.type_annotation) },
                     );
diff --git a/crates/oxc_parser/src/js/class.rs b/crates/oxc_parser/src/js/class.rs
index 50477a9849cb1..3cbcae2888c61 100644
--- a/crates/oxc_parser/src/js/class.rs
+++ b/crates/oxc_parser/src/js/class.rs
@@ -294,7 +294,8 @@ impl<'a> ParserImpl<'a> {
             if optional {
                 self.error(diagnostics::optional_accessor_property(optional_span));
             }
-            self.parse_class_accessor_property(span, key, computed, r#static, r#abstract).map(Some)
+            self.parse_class_accessor_property(span, key, computed, r#static, r#abstract, definite)
+                .map(Some)
         } else if self.at(Kind::LParen) || self.at(Kind::LAngle) || r#async || generator {
             // LAngle for start of type parameters `foo<T>`
             //                                         ^
@@ -483,6 +484,7 @@ impl<'a> ParserImpl<'a> {
     }
 
     /// <https://github.com/tc39/proposal-decorators>
+    #[allow(clippy::fn_params_excessive_bools)]
     fn parse_class_accessor_property(
         &mut self,
         span: Span,
@@ -490,6 +492,7 @@ impl<'a> ParserImpl<'a> {
         computed: bool,
         r#static: bool,
         r#abstract: bool,
+        definite: bool,
     ) -> Result<ClassElement<'a>> {
         let type_annotation =
             if self.ts_enabled() { self.parse_ts_type_annotation()? } else { None };
@@ -510,6 +513,7 @@ impl<'a> ParserImpl<'a> {
             value,
             computed,
             r#static,
+            definite,
             type_annotation,
         ))
     }
diff --git a/crates/oxc_traverse/src/generated/ancestor.rs b/crates/oxc_traverse/src/generated/ancestor.rs
index 5f91d1e5ca78d..5d118a2a99cfa 100644
--- a/crates/oxc_traverse/src/generated/ancestor.rs
+++ b/crates/oxc_traverse/src/generated/ancestor.rs
@@ -7319,6 +7319,7 @@ pub(crate) const OFFSET_ACCESSOR_PROPERTY_KEY: usize = offset_of!(AccessorProper
 pub(crate) const OFFSET_ACCESSOR_PROPERTY_VALUE: usize = offset_of!(AccessorProperty, value);
 pub(crate) const OFFSET_ACCESSOR_PROPERTY_COMPUTED: usize = offset_of!(AccessorProperty, computed);
 pub(crate) const OFFSET_ACCESSOR_PROPERTY_STATIC: usize = offset_of!(AccessorProperty, r#static);
+pub(crate) const OFFSET_ACCESSOR_PROPERTY_DEFINITE: usize = offset_of!(AccessorProperty, definite);
 pub(crate) const OFFSET_ACCESSOR_PROPERTY_TYPE_ANNOTATION: usize =
     offset_of!(AccessorProperty, type_annotation);
 
@@ -7365,6 +7366,11 @@ impl<'a> AccessorPropertyWithoutDecorators<'a> {
         unsafe { &*((self.0 as *const u8).add(OFFSET_ACCESSOR_PROPERTY_STATIC) as *const bool) }
     }
 
+    #[inline]
+    pub fn definite(&self) -> &bool {
+        unsafe { &*((self.0 as *const u8).add(OFFSET_ACCESSOR_PROPERTY_DEFINITE) as *const bool) }
+    }
+
     #[inline]
     pub fn type_annotation(&self) -> &Option<Box<'a, TSTypeAnnotation<'a>>> {
         unsafe {
@@ -7418,6 +7424,11 @@ impl<'a> AccessorPropertyWithoutKey<'a> {
         unsafe { &*((self.0 as *const u8).add(OFFSET_ACCESSOR_PROPERTY_STATIC) as *const bool) }
     }
 
+    #[inline]
+    pub fn definite(&self) -> &bool {
+        unsafe { &*((self.0 as *const u8).add(OFFSET_ACCESSOR_PROPERTY_DEFINITE) as *const bool) }
+    }
+
     #[inline]
     pub fn type_annotation(&self) -> &Option<Box<'a, TSTypeAnnotation<'a>>> {
         unsafe {
@@ -7470,6 +7481,11 @@ impl<'a> AccessorPropertyWithoutValue<'a> {
         unsafe { &*((self.0 as *const u8).add(OFFSET_ACCESSOR_PROPERTY_STATIC) as *const bool) }
     }
 
+    #[inline]
+    pub fn definite(&self) -> &bool {
+        unsafe { &*((self.0 as *const u8).add(OFFSET_ACCESSOR_PROPERTY_DEFINITE) as *const bool) }
+    }
+
     #[inline]
     pub fn type_annotation(&self) -> &Option<Box<'a, TSTypeAnnotation<'a>>> {
         unsafe {
@@ -7529,6 +7545,11 @@ impl<'a> AccessorPropertyWithoutTypeAnnotation<'a> {
     pub fn r#static(&self) -> &bool {
         unsafe { &*((self.0 as *const u8).add(OFFSET_ACCESSOR_PROPERTY_STATIC) as *const bool) }
     }
+
+    #[inline]
+    pub fn definite(&self) -> &bool {
+        unsafe { &*((self.0 as *const u8).add(OFFSET_ACCESSOR_PROPERTY_DEFINITE) as *const bool) }
+    }
 }
 
 pub(crate) const OFFSET_IMPORT_EXPRESSION_SPAN: usize = offset_of!(ImportExpression, span);