Physicist Brian Cox among stars at Wimbledon on middle Sunday

Oscar-winning actor Daniel Kaluuya, Olympic gold medallist Sir Ben Ainslie, former Pointless co-presenter Richard Osman and singer Ellie Goulding also took their seats in the Royal Box.

Also present was Love Actually director Richard Curtis, who signed a letter asking tournament organisers to remove Barclays as sponsors of the competition on climate change grounds ahead of the event kicking off on Monday.

Away from Centre Court on Sunday, umpire John Blom warned spectators not to pop champagne when players are about to serve.

Russian teenager Mirra Andreeva had been playing against Anastasia Potapova on Court Three when the umpire gave the warning to a laughing crowd.

He said: “Ladies and gentlemen, please if you are opening a bottle of champagne, don’t do it as the players are about to serve.”

Tennis fans donned raincoats and put up their umbrellas in the queue for the tournament on Sunday morning.

Forecasters had warned of heavy rain between 9am and 10am, and then again at around midday, on Sunday in south-west London but conditions have remained relatively dry so far.

Met Office forecaster Simon Partridge predicted tennis fans should see a full day’s play.

Mr Partridge said: “Wimbledon is expected to remain dry and brighter this afternoon, with a very low risk of the odd shower, nothing particularly heavy or persistent. They might not have to stop for it.

“The air temperature at Wimbledon will reach a maximum of 23C and it will be less humid than recent days.

“If you are there you should get a full day’s play.”

In the morning, hopeful spectators said they were undaunted by the possibility of showers.

Two people near the front of Sunday’s queue, standing under an umbrella to shelter from light drizzle, told the PA news agency that rain poses “no problem”.

When asked if they were worried about getting wet, Ilaria, 28, and Lorenzo, 31, from Italy, said: “No problem. Zero.”

The pair are attending to cheer on Novak Djokovic and Matteo Berrettini.

It is their first time at Wimbledon and before the gates had even opened they were already saying they will come back next year.

“I think it is one of five most beautiful days of our lives,” Lorenzo said.

Sara Murphy, 34, and Joseph Murphy, 13, from Liverpool, told PA they were similarly unbothered by warnings of further rain.

Ms Murphy said she was “prepared for the weather” as she sat in the queue under a large black umbrella.

Joseph, when asked if he was concerned about the rain, said he “never got told” of potential bad weather but denied having second thoughts about attending the tournament as they have secured wristbands for the roofed Centre Court.

Asked if they were disappointed about the fact that no British singles players will be competing for the title, Ms Murphy said: “We’re only here for Djokovic.”

Hopes of a British Wimbledon champion ended at SW19 after no UK players made it through to Sunday’s fourth round.

Katie Boulter was beaten by last year’s champion Elena Rybakina in the third round on Saturday night.

But Boulter will play again in the second round of the mixed doubles on Sunday, partnering up with her boyfriend, Australian player Alex De Minaur.

Sunday could also see an awkward encounter when Ukrainian Elina Svitolina plays Belarusian Victoria Azarenka.

The Ukrainian has refused to shake hands with a Belarusian opponent before.

Svitolina was beaten by Belarusian Aryna Sabalenka at the French Open in June and walked straight past her opponent at the end of the match.

Sabalenka stood at the net waiting for a handshake and there were loud boos as Svitolina walked straight past her without acknowledging her.

The Ukrainian player had previously urged tennis to focus on the suffering in Ukraine rather than issues the war is causing within the sport.