diff --git a/src/Database/Expression/QueryExpression.php b/src/Database/Expression/QueryExpression.php
index 3f996e00532..1336d614230 100644
--- a/src/Database/Expression/QueryExpression.php
+++ b/src/Database/Expression/QueryExpression.php
@@ -434,6 +434,11 @@ protected function _addConditions(array $conditions, array $types) {
 			if ($numericKey && empty($c)) {
 				continue;
 			}
+			
+			if (is_callable($c)) {
+				$expr = new QueryExpression([], $typeMap);
+				$c = $c($expr, $this);
+			}
 
 			if ($numericKey && is_string($c)) {
 				$this->_conditions[] = $c;