Lockdown Games: What's this tennis great up to?

With all sporting activities around the world coming to a complete halt, Swiss tennis great Roger Federer devised an unique training method to spend time at home, while also entertaining his fans.

VIDEO: Kind courtesy Roger Federer/Instagram

Interestingly, the 20-time Grand Slam champion can be seen practicing a sole tennis drill at home wearing a hat.

'Here's a helpful solo drill. Let's see what you got! Reply back with a video and I'll provide some tips. Choose your hat wisely,' Federer said on Tuesday.

Federer also challenged India cricket captain Virat Kohli, football ace Cristiano Ronaldo, fellow tennis players Rafael Nadal, Serena Williams, Novak Djokovic and Formula One champion Lewis Hamilton and other sporting greats to come up with similar ideas of their own.

Federer reached out to the needy during the coronavirus pandemic, with the former world number one and his wife donating one million Swiss Francs ($1.02 million) to vulnerable families in his native Switzerland.

'These are challenging times for everyone and nobody should be left behind,' Federer said. 'Mirka and I have decided to donate one million Swiss drancs for the most vulnerable families in Switzerland.'

Tennis has been suspended for a few months, with this year's Wimbledon cancelled and the French Open postponed to September.

Federer, a 20 time Grand Slam winner, is currently recovering from knee surgery he underwent last month and was targeting a return in June in time for Wimbledon, which has now been cancelled following the suspension of professional tennis extended to July 13.

While Federer, who turns 39 on August 8, is well insulated from the shutdown's financial fallout it could well impact his hopes of adding to his record haul of Grand Slam titles.

The last of Federer's Grand Slams came at the 2018 Australian Open and the closest he came to adding to his tally was at last year's Wimbledon final.

Federer's last match was at the Australian Open semi-finals before he underwent keyhole surgery on his knee in February.

His next chance at a Grand Slam would be the US Open, scheduled in New York from August 31 to September 14.

The French Open, an event he has skipped in the past, has been rearranged from May to September -- a week after the US Open.