Hasselhoff Fell Off the Wagon at Simon's Party

Sources tell TMZ David Hasselhoff was indeed drinking at Simon Cowell's birthday party in London this past weekend.

According to The Sun, staff at the party had to help The Hoff leave through a back entrance after he spent two hours pounding booze. The Sun claims David was so wasted that, "he kept swearing ... he couldn't walk."

Sometime after the party, Hoff -- who has famously battled alcohol problems in the past -- allegedly got wasted again and punched a doctor at the British hotel he was staying at during the trip.