I guess he just couldn't resist!

Beyonce joined Jay-Z onstage during the final show of his opening run at the Barclays Center in Brooklyn, New York last night, and when the duo performed "Crazy in Love," the rapper gave his wife a playful smack on the butt!

Bey also performed “Diva” and the two sang “Young Forever," and at the end of the show Jay joked, “Of course I had to let BK touch the stage in BK– well BKC now." Check out the video above, and skip ahead to 4:57 to see Jay getting a handful of Bey's booty!