diff --git a/pytm/template_engine.py b/pytm/template_engine.py
index a34c3b5..d9be4e1 100644
--- a/pytm/template_engine.py
+++ b/pytm/template_engine.py
@@ -11,10 +11,10 @@ def format_field(self, value, spec):
             template = spec.partition(':')[-1]
             if type(value) is dict:
                 value = value.items()
-            return ''.join([template.format(item=item) for item in value])
+            return ''.join([self.format(template, item=item) for item in value])
         elif spec == 'call':
             return value()
         elif spec.startswith('if'):
             return (value and spec.partition(':')[-1]) or ''
         else:
-            return super(SuperFormatter, self).format_field(value, spec)
\ No newline at end of file
+            return super(SuperFormatter, self).format_field(value, spec)