Beckham was talking to DeGeneres about his family's longtime friendship with Bieber when the 26-year-old "Changes" singer unexpectedly popped out of a nearby box and screamed.
The 44-year-old athlete barely flinched and instead looked slightly surprised and delighted by the random appearance.
"I really didn't think that was going to happen," Beckham said, leading Bieber to hug him, apologize, and leave.