The three year deal will see the Swiss firm have its brand name around Old Trafford.
Saudi Telecom, Budweiser and Seoul Metropolitan Government has in recent months committed themselves to Manchester United.
“We are in difficult economic times, but this deal shows that there are still deals to be done,” United chief executive David Gill told MUTV. “It’s not to say that football is not going to be impacted by that.
“But if you can combine the strength of a brand like Manchester United and a company like Hublot then you have got a wonderful combination.”
“We’re delighted to welcome such a prestigious partner as Hublot to Manchester United,” added Gill.
“Their reputation for excellence and innovation makes them a fitting and exciting sponsor. Sir Alex is well known as a stickler for timekeeping on and off the pitch – now we have a partner that shares his passion!”
Hublot chief executive Jean-Claude Biver added: “Manchester United is the number one club in the world. We’re very proud to be the official timekeeper of the most prestigious football club in the world.”