They're two of the biggest names in sport and now they will be playing together at the most famous tennis tournament in the world, Wimbledon.
Britain's Andy Murray has confirmed he will play mixed doubles with Serena Williams at this year's tournament.
Williams, who is a seven-time Wimbledon women's singles champion, had earlier told journalists: "If you guys really want it... all right, done."
Murray said: "Serena is obviously a brilliant player, has a great doubles record and is brilliant on grass obviously. She's arguably the best player ever."
The pair are expected to play their first match together on Thursday.
Sixty-four teams compete in the mixed doubles, which is played over the best of three sets.