Roger Federer challenged celebrities and fans to join in a volleying drill on social media on Tuesday.
With the ATP Tour suspended due to the coronavirus pandemic, the 20-time grand slam champion looked to engage fans on social media.
In a video posted on Twitter, Federer – wearing a panama hat – volleyed a ball repeatedly against a wall at close range, and asked others to do likewise.
"Here's a helpful solo drill. Let's see what you got!" the Swiss great wrote.
"Reply back with a video and I'll provide some tips. Choose your hat wisely #tennisathome."
Many fans took up the challenge, with Federer replying to several efforts.