Roger Federer reacted to Prince William and Kate Middleton's tweet when the couple shared a post ahead of Wimbledon Tennis tournament.
"Anyone for TENNIS," read a tweet carrying a picture of two chairs from the tennis court on the official account of the Prince and Princess of Wales.
"Count me in," Federer wrote as he quote-tweeted the royal couple's post.
The former tennis player's reply was viewed by half a million people within minutes after he had reacted to Kate and William's tweet.
Roger Federer was ranked world No. 1 in singles by the Association of Tennis Professionals (ATP) for 310 weeks, including a record 237 consecutive weeks, and finished as the year-end No. 1 five times.
He won 103 singles titles on the ATP Tour, the second most of all time, including 20 major men's singles titles, a record eight men's singles Wimbledon titles, an Open Era joint-record five men's singles US Open titles, and a joint-record six year-end championships.
In his home country, he is regarded as "the greatest and most successful" Swiss sportsperson in history.