Sir Jim Ratcliffe will run the London Marathon – then race across the capital for Manchester United's FA Cup semi-final.
The 71-year-old, who took a 25 per cent stake in his boyhood club at the turn of the year, is aiming to beat his personal best of four hours and 32 minutes.
And with United taking on Coventry in a 3.30pm kick-off, he will head straight from the finishing line at The Mall to Wembley Stadium.
The elite men's runners go off at 10am, with the rest of the group following behind.