diff --git a/NEWS.md b/NEWS.md
index a96a2e4b02..011b3c6be1 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,6 +1,8 @@
 
 # ggplot2 (development version)
 
+* `update_geom_defaults()` and `update_stat_defaults()` have a reset mechanism
+  when using `new = NULL` and invisible return the previous defaults (#4993).
 * `coord_map()` and `coord_polar()` throw informative warnings when used
   with the guide system (#5707).
 * When passing a function to `stat_contour(breaks)`, that function is used to
diff --git a/R/geom-defaults.R b/R/geom-defaults.R
index afd2e598d4..8b81eeef94 100644
--- a/R/geom-defaults.R
+++ b/R/geom-defaults.R
@@ -3,7 +3,9 @@
 #' @param stat,geom Name of geom/stat to modify (like `"point"` or
 #'   `"bin"`), or a Geom/Stat object (like `GeomPoint` or
 #'   `StatBin`).
-#' @param new Named list of aesthetics.
+#' @param new One of the following:
+#'  * A named list of aesthetics to serve as new defaults.
+#'  * `NULL` to reset the defaults.
 #' @keywords internal
 #' @export
 #' @examples
@@ -16,7 +18,7 @@
 #' ggplot(mtcars, aes(mpg, wt)) + geom_point()
 #'
 #' # reset default
-#' update_geom_defaults("point", aes(color = "black"))
+#' update_geom_defaults("point", NULL)
 #'
 #'
 #' # updating a stat's default aesthetic settings
@@ -29,27 +31,45 @@
 #'   geom_function(fun = dnorm, color = "red")
 #'
 #' # reset default
-#' update_stat_defaults("bin", aes(y = after_stat(count)))
+#' update_stat_defaults("bin", NULL)
 #'
 #' @rdname update_defaults
 update_geom_defaults <- function(geom, new) {
-  g <- check_subclass(geom, "Geom", env = parent.frame())
-  old <- g$default_aes
-  new <- rename_aes(new)
-  new_names_order <- unique(c(names(old), names(new)))
-  new <- defaults(new, old)[new_names_order]
-  g$default_aes[names(new)] <- new
-  invisible()
+  update_defaults(geom, "Geom", new, env = parent.frame())
 }
 
 #' @rdname update_defaults
 #' @export
 update_stat_defaults <- function(stat, new) {
-  g <- check_subclass(stat, "Stat", env = parent.frame())
-  old <- g$default_aes
-  new <- rename_aes(new)
-  new_names_order <- unique(c(names(old), names(new)))
-  new <- defaults(new, old)[new_names_order]
-  g$default_aes[names(new)] <- new
-  invisible()
+  update_defaults(stat, "Stat", new, env = parent.frame())
+}
+
+cache_defaults <- new_environment()
+
+update_defaults <- function(name, subclass, new, env = parent.frame()) {
+  obj   <- check_subclass(name, subclass, env = env)
+  index <- snake_class(obj)
+
+  if (is.null(new)) { # Reset from cache
+
+    old <- cache_defaults[[index]]
+    if (!is.null(old)) {
+      new <- update_defaults(name, subclass, new = old, env = env)
+    }
+    invisible(new)
+
+  } else { # Update default aesthetics
+
+    old <- obj$default_aes
+    # Only update cache the first time defaults are changed
+    if (!exists(index, envir = cache_defaults)) {
+      cache_defaults[[index]] <- old
+    }
+    new <- rename_aes(new)
+    name_order <- unique(c(names(old), names(new)))
+    new <- defaults(new, old)[name_order]
+    obj$default_aes[names(new)] <- new
+    invisible(old)
+
+  }
 }
diff --git a/man/update_defaults.Rd b/man/update_defaults.Rd
index e009b99d32..8006bf8246 100644
--- a/man/update_defaults.Rd
+++ b/man/update_defaults.Rd
@@ -10,7 +10,11 @@ update_geom_defaults(geom, new)
 update_stat_defaults(stat, new)
 }
 \arguments{
-\item{new}{Named list of aesthetics.}
+\item{new}{One of the following:
+\itemize{
+\item A named list of aesthetics to serve as new defaults.
+\item \code{NULL} to reset the defaults.
+}}
 
 \item{stat, geom}{Name of geom/stat to modify (like \code{"point"} or
 \code{"bin"}), or a Geom/Stat object (like \code{GeomPoint} or
@@ -29,7 +33,7 @@ GeomPoint$default_aes
 ggplot(mtcars, aes(mpg, wt)) + geom_point()
 
 # reset default
-update_geom_defaults("point", aes(color = "black"))
+update_geom_defaults("point", NULL)
 
 
 # updating a stat's default aesthetic settings
@@ -42,7 +46,7 @@ ggplot(data.frame(x = rnorm(1e3)), aes(x)) +
   geom_function(fun = dnorm, color = "red")
 
 # reset default
-update_stat_defaults("bin", aes(y = after_stat(count)))
+update_stat_defaults("bin", NULL)
 
 }
 \keyword{internal}
diff --git a/tests/testthat/test-geom-.R b/tests/testthat/test-geom-.R
index 409aa19b8f..61063d5d95 100644
--- a/tests/testthat/test-geom-.R
+++ b/tests/testthat/test-geom-.R
@@ -6,7 +6,21 @@ test_that("aesthetic checking in geom throws correct errors", {
   expect_snapshot_error(check_aesthetics(aes, 4))
 })
 
-
+test_that("geom defaults can be set and reset", {
+  l <- geom_point()
+  test <- l$geom$use_defaults(data_frame0())
+  expect_equal(test$colour, "black")
+
+  inv <- update_geom_defaults("point", list(colour = "red"))
+  test <- l$geom$use_defaults(data_frame0())
+  expect_equal(test$colour, "red")
+  expect_equal(inv$colour, "black")
+
+  inv <- update_geom_defaults("point", NULL)
+  test <- l$geom$use_defaults(data_frame0())
+  expect_equal(test$colour, "black")
+  expect_equal(inv$colour, "red")
+})
 
 test_that("updating geom aesthetic defaults preserves class and order", {
 
@@ -23,7 +37,7 @@ test_that("updating geom aesthetic defaults preserves class and order", {
 
   expect_equal(updated_defaults, intended_defaults)
 
-  update_geom_defaults("point", original_defaults)
+  update_geom_defaults("point", NULL)
 
 })
 
@@ -46,6 +60,6 @@ test_that("updating stat aesthetic defaults preserves class and order", {
 
   expect_equal(updated_defaults, intended_defaults)
 
-  update_stat_defaults("bin", original_defaults)
+  update_stat_defaults("bin", NULL)
 
 })