In the legendary crossover the world never knew it needed, tennis star Serena Williams hopped on stage with Kendrick Lamar during the Super Bowl halftime show for his epic Drake diss track, “Not Like Us”—and she served. Not a tennis ball. Just served.

Williams was only shown on television for a few seconds on Sunday, but it was enough to make most of America audibly gasp having witnessed the second-most exciting surprise of the night (the first being the Philadelphia Eagles’ 24-0 halftime lead over the Kansas City Chiefs.)

Williams opened up about how she got the cameo in an emotional post on social media on Tuesday:

“When @kendricklamar and team called and was like ‘we’ve been trying to do something forever, what about this? We loved your crip walk at the Olympics after you won the gold medal,’” Williams wrote on Instagram.

“I’m like Super Bowl? Are you serious? When in the world would I ever be able to dance at a super bowl? (Never) let’s do it!”

Williams also shared an extended behind-the-scenes video in which she was seen practicing the infamous crip walk with her 7-year-old daughter, Olympia, and the show’s choreographers in the days leading up to the big game. 

The 23-time Grand Slam champion admitted shortly after her Super Bowl halftime cameo that she would have been fined at Wimbledon if she pulled out those dance moves on the tennis court.

But, as Williams stated in her recent Instagram post, “I knew my winning dance after the @olympics would pay off one day. End of story.”