The Portuguese had been heavily linked with the club following the dismissal of Louis van Gaal on Monday
Manchester United are expected to confirm the worst-kept non-secret in football as they appoint Jose Mourinho as their permanent manager on Thursday afternoon.
United had been heavily linked with Mourinho following the dismissal of Louis van Gaal on Monday, just two days after the Dutchman lifted a record-equalling 12th FA Cup.
Mourinho was sacked before Christmas last season after a run of poor results with Chelsea saw them slip towards the relegation zone.
The Portuguese manager had enjoyed successful spells with Chelsea in the mid-2000s, winning the Premier League in consecutive seasons in 2004 and 2005. He has also won domestic titles with Porto, Inter Milan and Real Madrid.
Mourinho becomes the third manager appointed by Manchester United in the post-Ferguson era.
Reports indicate he met United officials at a London hotel this afternoon, where he signed his contract.
The club are still yet to make an announcement on the appointment.