Roy Keane's testimonial is likely to attract the biggest gathering of away fans ever seen at a British game.
Keane's current club Celtic have requested 20,000 tickets for the May 9th game.
After consulting safety officers, United have decided the only way they can accommodate such a massive number of supporters is by allocating Celtic the entire North Stand, which holds approximately 25,500.
It is still anticipated Celtic will sell their entire allocation, helping to swell the attendance for the former United skipper to well over 70,000.
Keane has already pledged to give away 1,000 tickets to Manchester schoolchildren and local United supporters clubs and it is widely assumed the proceeds, which are likely to be in excess of £2.5million, will be donated to the Corkman's favourite charities.
Meanwhile, United expect to smash the club record for a home game at Old Trafford when they entertain Arsenal on Sunday.
With more seats set to be made available in the new quadrants, club officials are confident of exceeding the 70,504 they attracted for a league game against Aston Villa in 1920.
However, even when the expansion is fully completed, Old Trafford's capacity will still fall short of the 76,962 who saw the FA Cup semi-final between Wolves and Grimsby at the ground in 1946.
Meanwhile, the English FA maintain the race to succeed Sven-Goran Eriksson remains wide open despite speculation that Steve McClaren has assumed pole position.
Until now, Martin O'Neill has been regarded as the front-runner to become the next England manager but rumours swept through the north-east the Middlesbrough manager McClaren was now the favourite.
The FA's nominations group have whittled the original list of contenders down to three or four people which are being kept so secret that not even yesterday's board meeting was told the names of the candidates.
Both O'Neill and McClaren are understood to be on the shortlist, but the FA are insistent there is a level playing field for all the remaining candidates.
