The 'Dallas' actor will guest star in one episode early in the season, playing Max's weekly booty call, reported Deadline.
The waitress, played by Kat Dennings, shares such a casual relationship with Metcalfe's character that she doesn't even know his name.
Metcalfe, who has also starred in 'Desperate Housewives', wrote about his experience on Whosay, thanking the "unbelievably talented cast and crew" for being "so cool and kind".
Season four of '2 Broke Girls' will begin in the US on CBS on October 27.