Manchester United have accepted an £80m ($131.6m or €93.9m) offer from Real Madrid for Cristiano Ronaldo.
A statement on the United website confirmed that a deal for the 24-year-old should be completed by the end of the month.
• Editor John Brewin on the inevitability of Ronaldo's £80m move to Real Madrid
''Manchester United have received a world-record, unconditional offer of £80m for Cristiano Ronaldo from Real Madrid.
''At Cristiano's request - who has again expressed his desire to leave - and after discussion with the player's representatives, United have agreed to give Real Madrid permission to talk to the player.
''Matters are expected to be concluded by June 30. The club will not comment until further notice.''
Ronaldo has long been a target for the Spanish giants, whose president Florentino Perez vowed earlier this week to do ''everything possible'' to take the forward to the Bernabeu. The club now hope to agree personal terms with Ronaldo in the next few days.
The 24-year-old is currently on holiday in Los Angleles and told U.S. broadcaster Fox Sports that he was "flattered" by Madrid's interest.
"It's flattering when two of the top teams in the world want you to play for them. The deal is historic. €93m is quite a sum of money.
"I learned about the deal here in L.A. and have heard from my people that Manchester United has accepted. However I have also been told that Madrid want to have a medical team look at me as expected."
It is now certain that a second era of galacticos has begun at Madird, with news of Ronaldo's £80m deal coming in the same week that Perez agreed a £59m deal ($97m or €69m) to sign Kaka. Which means in less than a week, Madrid have committed to spending an incredible £139m ($228m or €162.9m) on just two players.
In Perez's previous stint as Madrid president he oversaw the acquisitions of global stars Ronaldo (£23.2m), David Beckham (£24.5m), Luis Figo (£37m), as well as Zinedine Zidane in what was a then world record of £46.7m.
The news is bound to be greeted with some scepticism by United fans who have repeatedly been told no deal had been agreed for the sale of FIFA's World Player of the Year. That came in the face of regular statements from Spain that the former Sporting Lisbon star was bound for the Bernabeu.
It was even suggested Ronaldo would be due upwards of £20m in compensation from Real if the deal did not go through by June 30, the date United now state themselves is when they expect matters to be concluded.
As it now seems a matter of when, rather than if, a world record transfer will be completed, Sir Alex Ferguson might wish to explain why he has gone back on his famous comment in December last year that he would not ''sell that mob a virus''.
It is the first time for many years United would have allowed a player to leave they were not happy about losing.
Yet some supporters may be pleased that at least another drawn-out transfer saga, such as the one 12 months ago, will not be played out in public.
At least the money could be reinvested in a squad that almost proved good enough to win back-to-back Champions League trophies, in addition to a hat-trick of Premier League titles.
In reshaping a squad that looked almost certain to lose Carlos Tevez as well, though the cash from Real Madrid may change that, Ferguson might be able to offer Wayne Rooney a more permanent central striking role and fulfil the promise he has shown on the international stage this season.
The name of Bayern Munich's Franck Ribery is bound to crop up as a potential replacement, although the 27-year-old seems hugely overpriced at the £40m figure being bandied about in some quarters. Wigan's Antonio Valencia has long been touted as a summer signing.
Ferguson will certainly be making plans already to ensure his new faces are on board before United head to Asia for their pre-season tour in five weeks.
Amid the frenzy over Ronaldo's impending departure, it is bound to be asked whether the current debt hanging over United of almost £700m has played any part in the decision to accept Real's huge bid.
While Ferguson has always backed the Glazer family for the backing he has received, supporters will now be interested to see whether their manager is handed all the funds received from Spain, plus an annual transfer kitty said to be around £25m.
With Edwin van der Sar, Ryan Giggs, Paul Scholes and Gary Neville all reaching the end of their careers, it promises to be a far more testing summer than Ferguson might have realised.
And, for all the petulance and pouting for which Ronaldo is so famed, filling the void created by the loss of his immense talent may prove difficult.