Mason Mount set his sights on winning major trophies with Manchester United after the England midfielder completed his move from Chelsea for a reported fee of £55 million ($70 million) on Wednesday.

Mount agreed a five-year contract with United with the option of a further year, and becomes Erik ten Hag's first major close-season signing.

The 24-year-old graduated from Chelsea's youth academy and made 129 Premier League appearances for the Stamford Bridge club, scoring 27 goals.

"It's never easy leaving the club where you grew up, but Manchester United will provide an exciting new challenge for the next phase of my career," Mount said.

"Having competed against them, I know just how strong a squad it is that I'm joining, and I can't wait to be part of this group's drive to win major trophies."

Mount won the Champions League with Chelsea in 2021, providing the defence-splitting pass that led to Kai Havertz's winner in the final against Manchester City.

United manager Ten Hag will hope Mount can provide energy and goals from both a central midfield berth and on the flanks at Old Trafford.

Describing himself as "hugely ambitious", Mount cannot wait to start the new chapter in his career.

"Everyone can see that the club has made big steps forward under Erik ten Hag," said Mount, whose fee could rise by a further £5 million in add-ons.

"Having met with the manager and discussed his plans, I couldn't be more excited for the seasons ahead, and am ready for the hard work expected here.

"I am hugely ambitious. I know how amazing it feels to win major trophies and what it takes to do it. I will be giving everything to experience that again at Manchester United."

After emerging as a key figure in Chelsea's team under Frank Lampard and then Thomas Tuchel, Mount endured a dip in form last season.

Hampered by injuries, he struggled during a turbulent campaign marred by the sackings of Tuchel and his successor Graham Potter.

Chelsea were reported to have made several contract offers to Mount in a bid to keep the homegrown star at Stamford Bridge.

Mount had signalled his move to United by posting an emotional farewell message to Chelsea fans on Instagram late on Tuesday.

"I feel you deserve more than just a written statement, so I wanted to tell you directly how grateful I've been for all of your support over the last 18 years," he said.

"I know some of you won't be happy with my decision, but it's what's right for me at this moment in my career."

Mount has made 36 England appearances, helping the Three Lions reach the European Championship final in 2021 and featuring at last year's World Cup in Qatar.

Manchester United football director John Murtough, described Mount as an "extremely intelligent footballer" who would be a "perfect fit" at Old Trafford.

"We have admired his talents for a long time, so we are delighted that he has chosen to take the next steps in his career here at Old Trafford," he said.