The testimonial, usually held to honour a player's long service at a club or to mark retirement, are supposed to be light-hearted, non-competitive affairs that raise millions of pounds for charity.
But that has not always been the case.
From celebrities and brawls to handsome pay-offs and injuries, BBC Sport takes a look at the dos and don'ts of hosting a testimonial.
Testimonials began as a way to set up a player for retirement, back when wages paled in comparison to those today, with money made from the game paid to the player.
Former Arsenal and England goalkeeper David Seaman made £600,000 tax free from his match in 2001.
The recent trend has been for a player to donate the proceeds to charity, which began with former Republic of Ireland and Sunderland striker Niall Quinn.
Quinn gave an estimated £1m raised at his benefit match to charity.
Rooney has followed suit and said proceeds from the game on 3 August will be split between the NSPCC, Alder Hey Children's Hospital, Claire House Children's Hospice and Manchester United's own foundation.
Former Coventry defender David Busst suffered one of the worst injuries in football in 1996 against Manchester United, which forced him into retirement aged 29.
The Sky Blues granted Busst a testimonial match against United to benefit him and his family.
The match was memorable for being Eric Cantona's last game for United, the Frenchman retiring from football two days later.
Didier Drogba, retired Formula 1 driver Michael Schumacher, Lothar Matthaeus, Andriy Shevchenko and Philipp Lahm all turned out for former Germany captain Michael Ballack's testimonial in 2013.
Cristiano Ronaldo could be returning to Old Trafford for Rooney's testimonial while the England striker made his return to Goodison Park for Duncan Ferguson's testimonial in August.
Then there were the stellar line-ups involved in Portugal legend Deco's benefit match in 2014 at the Estadio do Dragao.
The match was between Porto's 2004 Champions League winners and Barcelona's 2006 European champions, both teams that Deco had played for and players on show included Lionel Messi, Samuel Eto'o, and Edgar Davids.
But the stars are not always guaranteed to turn up.
George Best reportedly snubbed Manchester United team-mate Bobby Charlton's testimonial against Celtic in 1972 and spent the night drinking. The match at Old Trafford still attracted a crowd of 60,538, which was then a British record for a benefit match.
By August 2012, full-back Tony Hibbert had played 308 times for Everton, but had never scored for the Toffees.
He made amends in his testimonial, scoring a stunning free-kick in a 4-1 win over AEK Athens. And still after 15 seasons it remains his only goal for the club.
"The lads were saying to me in the changing room that it was like a fairytale," he said afterwards.
Former England striker Alan Shearer had injured his knee three weeks before his testimonial in 2006 so could not play a full role but he kicked the first and last ball of the match.
The Premier League's all-time top scorer came off the bench to score a penalty in injury-time to give Newcastle a 3-2 victory over Celtic.
Some managers must dread testimonials as much as they do the international break, crossing their fingers in the hope that their players come back in one piece.
Former England and Liverpool forward Peter Beardsley had just re-signed for Newcastle from Everton for £1.5m in 1993, when he took part in Ronnie Whelan's testimonial match at Anfield.
Beardsley sustained a triple fracture of his cheekbone in the second minute of the match after a collision with Neil Ruddock and was ruled out for six weeks.
And Manchester United great Denis Irwin lasted only 36 minutes of his own testimonial in 2000 against neighbours Manchester City when he hobbled off.
George Weah caught Irwin with a late tackle that left him with an ankle injury in a bad tempered affair.
Spare a thought for Walsall's stalwart midfielder Darren Wrack, whose testimonial against Wolves in 2008 attracted a crowd of only 1,330 to the Banks's Stadium, which has a capacity of 11,300.
Compare that to the game in September for Borussia Dortmund's Brazilian defender Dede to mark his 13 years at the club.
Dortmund's Westfalenstadion was filled with 81,359 fans, a record for a testimonial, and Dede marked the occasion by scoring a 40-yard lob.
Dennis Bergkamp chose the best time to hold his match as he bowed out of Arsenal after 11 years.
The Dutch legend's send-off coincided with the opening day of the Gunners' Emirates stadium in 2006 with a sell-out 60,000 crowd.
Paul Scholes marked his farewell from Manchester United with a trademark strike as the Reds beat  New York Cosmos 6-0 in 2011.
Except it proved not to be the midfielder's final appearance for United. The following year he was coaxed out of retirement by Sir Alex Ferguson and won an 11th league title before finally hanging up his boots.
Meanwhile, his manager had a very premature testimonial in 1999, half-way through his 27-year career at Old Trafford. He would eventually retire in 2013.
Southampton legend Claus Lundekvam had to pay a six-figure sum to returf the St Mary's pitch for his testimonial after 12 seasons with the Saints in 2008.
The reason... American rockers Bon Jovi.
Norway defender Lundekvam wanted to play Celtic but the only date the Scottish club could make meant there was not enough time after a Bon Jovi concert to reseed the St Mary's pitch.
So Lundekvam shelled out for a new pitch.
Just under 19,000 fans turned out to the match meaning the Norwegian was able to recoup all of the £250,000 he had forked out to stage the game.
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One Direction star Louis Tomlinson was left wincing in agony on the pitch after being clattered by Aston Villa's Gabriel Agbonlahor during a charity match at Celtic Park for former footballer Stiliyan Petrov.
The singer and Doncaster Rovers fan had to be substituted and was then physically sick on the sidelines following the rough treatment.
Agbonlahor later received abuse from One Direction fans on Twitter after the game for the tackle.
It was not the only testimonial game that Tomlinson has taken part in.
The singer was mobbed by hundreds of screaming girls as he played for his  hometown club in honour of long-serving Doncaster Rovers midfielder James Coppinger to mark 11 years at the club.
When Ajax organised a testimonial for their Dutch legend Johan Cruyff against Bayern Munich, the German team saw it as an opportunity to extract revenge for earlier defeats and hammered them 8-0.
It wasn't until 2006 that Bayern apologised for their behaviour. Karl-Heinz Rummenigge, who scored four in the game, and Gerd Muller both said they were not proud of the part they played. Goalkeeper Sepp Maier simply declared: "Sorry, Johan!"
Julian Dicks' testimonial in 2000 against Athletic Bilbao was anything but friendly - it erupted into a 17-man brawl.
The ugly scenes, which held up play for more than five minutes, came a minute before the break and happened when the former West Ham defender was not even on the pitch.
Some rash challenges from Nigel Winterburn on Joseba Etxeberria and then Igor Stimac on Ismael Urzaiz led to players from both sides pushing and shoving each other. The respective coaching staff also argued on the touchline before stewards and police rushed in to calm things down.
Referee Barry Knight ordered West Ham manager Harry Redknapp to substitute Paolo Di Canio while Bilbao coach Txetxu Rojo was told to take off Spanish international striker Etxeberria.
On the plus side, more than 14,000 fans turned up to pay tribute to Dicks for his 10 years' service - before his career was cut short by a knee injury that gave him a £200,000 pay day.
Australian footballer Brent Griffiths became the first man in history to be sent off for a last-ditch tackle on a giant barbecue sauce bottle.
Griffiths was taking part in a testimonial match for retiring Central Coast Mariners legend John Hutchinson.
The Hutch XI were leading 11-4 against the Mariners when the condiment-based mascot burst clear of the defence, only for Stoke-born Griffiths to commit the cynical foul and earn his marching orders.
When Wayne Rooney starts planning his testimonial game for next summer he may want to heed a few lessons from previous benefit matches.