The England striker thoroughly enjoyed last season's loan spell at the Stadium of Light and is full of admiration for Steve Bruce's Black Cats.
"I know quite a few of the players, so it'll be good to see them again, but, when it comes down to it, I'll be ruthless," Welbeck insisted on MUTV. "I just want to win the game. There's no friends out on the pitch.
"It was a great club to go to - a massive club and I really enjoyed my time there. The fans were great and I can't thank them enough."