Mason Mount spent 18 years with Chelsea and helped them win the Champions League in 2021 before suffering a dip in form last season as the Blues struggled through a turbulent campaign.
Mason Mount, who has penned a five-year deal, said he "can' wait to be part of this group's drive to win major trophies" at Old Trafford
Mason Mount scored twice as Chelsea beat Aston Villa on Sunday to strengthen their grip on a Premier League top-four place
Chelsea, prepping for their first Premier League season since Todd Boehly's consortium bought the club, beat Mexico's Club America 2-1 in an international club friendly in Las Vegas