We spotted some celebs from the world of Hollywood, cricket and comedy enjoying some tennis action and here we give a glimpse of them...
Federer, a 20-times Grand Slam champion and the world number three, won the last of his eight Wimbledon titles in 2017 and is seeded second this year behind top-ranked Novak Djokovic.
Images from Monday's action at the Australian Open.
Rafael Nadal kept the flag flying for the old guard at the Australian Open with a 6-3, 6-4, 6-2 victory over American Frances Tiafoe on Tuesday for a place in the semi-finals, where he will meet another next generation player in Stefanos Tsitsipas.
Novak Djokovic cruised past Germany's Jan-Lennard Struff 6-3, 6-1 on Wednesday to reach a record-equalling eighth Western & Southern Open semi-final in New York where he will face Spaniard Roberto Bautista Agut.
Nadal will not be playing at Wimbledon, having decided to rest, while eight-time champion Federer is showing signs that, at 39, the window of opportunity to win one more Slam is closing.
Cilic had never made it past the quarters in Paris but has now made the semis or better at all four majors.
Penpix of the top men's contenders at the 2021 Australian Open
This year's French Open welcomes up to 5,388 spectators
Homeland favorite Ashleigh Barty and Serbia's Novak Djokovic are the top seeds for the upcoming Australian Open.
Rafael Nadal extended his astonishing winning run on clay to 42 consecutive sets as he reached the semi-finals of the Barcelona Open with a 6-0, 7-5 victory over Slovakia's Martin Klizan.
Federer, Nadal and Djokovic had made it near impossible for their peers to live, and thrive, amongst them. But the coming generation, which hasn't been as scarred by defeat at the hands of the Big 3, may make tennis unpredictable again.
Top seed Simona Halep came back from a set down for the third time in the tournament to beat Kazakhstan's rising star Elena Rybakina 3-6, 6-3, 7-6(5) to win the Dubai Duty Free Tennis Championships for the second time on Saturday. In a battle that lasted nearly two-and-a-half hours, the match came down to a tiebreak where two shots that went agonisingly wide for Rybakina eventually decided the title in front of a noisy crowd that constantly chanted Halep's name.
Rafael Nadal's hopes of completing a rare calendar year Grand Slam ended on Thursday when the Spaniard pulled out of his highly-anticipated Wimbledon semi-final showdown against Australian Nick Kyrgios with an abdominal strain.
Nadal avenged his defeat to the 20-year-old Greek at the same stage of the Madrid Open a week ago
Jabeur advances to first WTA 100 final in Madrid in style.
Nadal, a Real fan despite his uncle Miguel Angel making over 200 appearances for arch-rivals Barcelona, was seen speaking to umpire Mohamed Lahyani about his team's 0-0 home draw with Real Betis on Saturday and was less than impressed with what he saw.
World number one Rafael Nadal won a battle of attrition against fellow left-hander Yoshihito Nishioka of Japan 7-6(4), 6-4 to seal Spain's spot in the final eight of the inaugural ATP Cup in Perth on Wednesday. Meanwhile his long-time rival, world number two Novak Djokovic, had an easier outing in Brisbane, strolling past Chile's Cristian Garin 6-3, 6-3 to stay undefeated in the new year.
Exodus of big guns opens up bottom half of men's draw
The Serbian top seed won a fourth successive title at the All England Club to take his overall Grand Slam tally to 21.
No tennis for four months, no problem for Rafael Nadal.
Ninth seed Auger-Aliassime, 21, was the dominant player in the first set and despite a wobble when serving at 6-5 he won a tiebreak courtesy of some Medvedev double-faults the Russian later blamed on the sweaty conditions.
Rohan Bopanna teamed up with Canada's Denis Shapovalov to enter the quarter-finals of the Rotterdam Open
Rafael Nadal had just beaten rising Greek force Stefanos Tsitsipas in a classic scrap at the ATP Finals but had no idea whether it was good enough to keep him in the tournament.
Rafael Nadal left German qualifier Yannick Maden no hope as he booked his ticket for the third round of the French Open in ruthless fashion with a 6-1, 6-2, 6-4 victory.
Andrey Rublev and Alexander Zverev clinched the Laver Cup for Team Europe with a 6-2, 6-7(4), 10-3 win over Team World's Reilly Opelka and Denis Shapovalov on Sunday in Boston.
IMAGES from Day 7 of the French Open, at Roland Garros, on Saturday.
Novak Djokovic extended his unbeaten start to the season to 15 matches as he swatted aside German veteran Philipp Kohlschreiber 6-3 6-1 with ease on Wednesday to reach the Dubai Tennis Championships quarter-finals.
Raducanu stormed into the third round of the Cincinnati Open
Images from Day 7 of the 2019 French Open in Paris on Saturday.
Federer rues missed chances in Tsitsipas thriller
Rafael Nadal said on Saturday "too many questions" still needed to be answered concerning Novak Djokovic's bid to play at the Australian Open, while other leading players lamented how the saga had overshadowed the year's first Grand Slam.
Images from Day 1 of the US Open in New York, on Monday.
Novak Djokovic secured a semi-final place at the ATP Finals with a 6-3, 6-2 victory over Russian Andrey Rublev on Wednesday, his 50th match win of the year, while Stefanos Tsitsipas withdrew from the tournament due to an elbow injury.
All players who want a visa to compete in the Australian Open will need to be fully vaccinated for COVID-19, the country's immigration minister said on Wednesday, putting Novak Djokovic's title defence and Grand Slam record bid in doubt.
World number one Novak Djokovic saved three match points to beat France's Gael Monfils 2-6, 7-6(8), 6-1 on Friday as he set up a final showdown at the Dubai Open with Greek second seed Stefanos Tsitsipas. Djokovic is yet to lose this year and the Australian Open champion extended his unbeaten run in 2020 to 17 matches with what was also his 17th win over Monfils.
Yet the warrior-like instincts kicked in and we were all reminded that Nadal, as long as he is standing, remains a physical and psychological force of nature on a tennis court.
A couple of months ago, the 35-year-old Spaniard was worried that he might never return to the court again.
'I hope that as an association we make the best decision for our business, for our health, for the tournaments, for public.'
Images from Day 3 of the 2020 French Open at Roland Garros, in Paris, on Tuesday.