The Dutch international striker has joined the Reds from Burnley until the end of the season, in a move that was completed on Friday.
Weghorst watched his new team-mates defeat Manchester City at Old Trafford on Saturday, before training with the squad on the following day. It was also confirmed on Sunday that Wout will wear the number 27 on the back of his United shirt, over the coming months.
Speaking in his first interview with club media, the 30-year-old explained the reason why he picked the number, one that he is yet to sport in his senior club career.