England internationals Siobhan Chamberlain and Alex Greenwood were the headline signings as Manchester United named their first ever squad for their entry to the FA Women's Championship.
United were granted a place in the second tier after announcing earlier this year they would be launching a women's team.
Both goalkeeper Chamberlain and defender Greenwood, regular members of the England squad bidding to qualify for next year's World Cup, have joined United from Liverpool.
"We've gone young, we've gone exciting, we've gone entertaining," manager Casey Stoney told the club's website.
"I'm more than aware that we're bringing 21 strangers together but I'm really excited about the squad and the future of this team."
Also joining the club is former United youth player Katie Zelem after a spell with Juventus and Jess Sigsworth, the joint-top scorer in Women's Super League 2 with Doncaster last season.