I have a table and want to replace newid() with values from another table. Here is an update statement:

UPDATE tbl1
SET tbl1.NewKey = NEWID()
FROM @List AS tbl1
WHERE tbl1.NewFlag = 1

I am going to update this table with values from my table instead of newid() :

drop TABLE if exists #tmpGUIDs
CREATE TABLE #tmpGUIDs
(
   rnum INT,
   uuid uniqueidentifier
)
-- filled here

How can I do this? As I see the problem is no keys to join these tables but here can be done something like “next value” from the tmp table