diff --git a/src/NQP/Actions.pm b/src/NQP/Actions.pm
index 22ce197..279030e 100644
--- a/src/NQP/Actions.pm
+++ b/src/NQP/Actions.pm
@@ -829,6 +829,12 @@ class NQP::RegexActions is Regex::P6Regex::Actions {
                               :pasttype<pastnode>, :node($/) );
     }
 
+    method assertion:sym<?{ }>($/) { 
+        make PAST::Regex.new( $<codeblock>.ast, 
+                              :subtype<zerowidth>, :negate( $<zw> eq '!' ),
+                              :pasttype<pastnode>, :node($/) );
+    }
+
     method assertion:sym<var>($/) {
         make PAST::Regex.new( '!INTERPOLATE_REGEX', $<var>.ast, 
                               :pasttype<subrule>, :subtype<method>, :node($/));
diff --git a/src/NQP/Grammar.pm b/src/NQP/Grammar.pm
index 3f439b7..e632f18 100644
--- a/src/NQP/Grammar.pm
+++ b/src/NQP/Grammar.pm
@@ -558,8 +558,12 @@ grammar NQP::Regex is Regex::P6Regex::Grammar {
         <?[$@]> <var=.LANG('MAIN', 'variable')>
     }
 
-    token assertion:sym<{ }> {
-        <?[{]> <codeblock>
+    # token assertion:sym<{ }> {
+    #     <?[{]> <codeblock>
+    # }
+
+    token assertion:sym<?{ }> {
+        $<zw>=[ <[?!]> <?before '{'> ] <codeblock>
     }
 
     token assertion:sym<name> {