diff --git a/mysql-test/main/function_defaults.result b/mysql-test/main/function_defaults.result
index 697e2e0d063..41bd0140a23 100644
--- a/mysql-test/main/function_defaults.result
+++ b/mysql-test/main/function_defaults.result
@@ -3145,3 +3145,28 @@ a	b	c
 2	2010-10-10 10:10:10	x
 drop table t1;
 set timestamp=default;
+#
+# MDEV-33790: Incorrect DEFAULT expression evaluated in UPDATE
+#
+create table t1 (
+a int,
+b timestamp default '2010-10-10 10:10:10' on update now(),
+c varchar(100) default 'x');
+create table t2 (a int primary key);
+insert t1 (a) values (1),(2);
+insert t2 (a) values (1),(2);
+select * from t1;
+a	b	c
+1	2010-10-10 10:10:10	x
+2	2010-10-10 10:10:10	x
+set timestamp=unix_timestamp('2011-11-11 11-11-11');
+update t1,t2 set b=default, c=default(b) where t1.a=1 and t1.a= t2.a;
+select * from t1;
+a	b	c
+1	2010-10-10 10:10:10	2010-10-10 10:10:10
+2	2010-10-10 10:10:10	x
+drop table t1, t2;
+set timestamp=default;
+#
+# End of 10.4 tests
+#
diff --git a/mysql-test/main/function_defaults.test b/mysql-test/main/function_defaults.test
index dd3ba109b2a..59776118e56 100644
--- a/mysql-test/main/function_defaults.test
+++ b/mysql-test/main/function_defaults.test
@@ -67,3 +67,26 @@ update t1 set b=default, c=default(b) where a=1;
 select * from t1;
 drop table t1;
 set timestamp=default;
+
+--echo #
+--echo # MDEV-33790: Incorrect DEFAULT expression evaluated in UPDATE
+--echo #
+
+create table t1 (
+  a int,
+  b timestamp default '2010-10-10 10:10:10' on update now(),
+  c varchar(100) default 'x');
+create table t2 (a int primary key);
+insert t1 (a) values (1),(2);
+insert t2 (a) values (1),(2);
+
+select * from t1;
+set timestamp=unix_timestamp('2011-11-11 11-11-11');
+update t1,t2 set b=default, c=default(b) where t1.a=1 and t1.a= t2.a;
+select * from t1;
+drop table t1, t2;
+set timestamp=default;
+
+--echo #
+--echo # End of 10.4 tests
+--echo #
diff --git a/sql/item.cc b/sql/item.cc
index f70775b86e8..c951a94b226 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -9748,11 +9748,15 @@ Item *Item_default_value::transform(THD *thd, Item_transformer transformer,
 }
 
 
-bool Item_default_value::associate_with_target_field(THD *thd,
-                                                     Item_field *field)
+bool Item_default_value::
+  associate_with_target_field(THD *thd,
+                              Item_field *field __attribute__((unused)))
 {
   m_associated= true;
-  arg= field;
+  /*
+    arg set correctly in constructor (can also differ from field if
+    it is function with an argument)
+  */
   return tie_field(thd);
 }