diff --git a/intrinsics/fnsub.go b/intrinsics/fnsub.go
index 8e46e8e48a..4a0f8caa0a 100644
--- a/intrinsics/fnsub.go
+++ b/intrinsics/fnsub.go
@@ -36,7 +36,7 @@ func FnSub(name string, input interface{}, template interface{}) interface{} {
 
 	case string:
 		// Look up references for each of the variables
-		regex := regexp.MustCompile(`\$\{([\.0-9A-Za-z]+)\}`)
+		regex := regexp.MustCompile(`\$\{([\.:0-9A-Za-z]+)\}`)
 		variables := regex.FindAllStringSubmatch(val, -1)
 		for _, variable := range variables {