Roger Federer will play tennis in Seattle for the first time and he’ll have a unique partner with him on the court: Bill Gates.

The tennis legend and 18-time Grand Slam champion will come to town on April 29 for a charity event supporting his foundation. He’ll play an exhibition match against American star John Isner at Key Arena and will also team up with Gates to play a one-set doubles match against Isner and a surprise celebrity partner.

The event marks the fourth “Match for Africa” day for the Roger Federer Foundation, which has given $29 million to support children’s education in six African countries and Federer’s home country of Switzerland. Tickets for the April 29 event go on sale this Thursday — proceeds will go toward the Roger Federer Charitable Fund/Roger Federer Foundation.

“I believe in the power of people,” Federer said in a statement. “We know that a good education is a decisive factor to empower children by allowing them to take their future into their own hands. With my foundation, we want to provide one million children with the opportunity for a quality education by the end of 2018. The Match for Africa 4 in Seattle will help us reach our ambitious goals. I am very grateful for this opportunity to collaborate with Bill Gates, who in my opinion is the world’s leading philanthropist.”

Gates is a long-time fan of tennis and a player himself — fellow billionaire Richard Branson just spoke about playing tennis with Gates during his visit to Seattle last week. Gates also supports charitable causes through his work at the Gates Foundation.

“I’m a huge fan of Roger’s work on and off the court,” Gates said in a statement. “We share a love of tennis (although he might be a little better than I am) and a belief that all children deserve a world-class education. Roger’s foundation does great work to support education in Africa, so it will be a lot of fun to play alongside him for such an important cause.”

The Starbucks Foundation, Rolex, Microsoft, and Nike are the presenting partners for the event in Seattle.