The 22-year-old attacker joins from fellow WSL side Tottenham Hotspur, following previous spells with PSG and Valerenga — where Celin secured a domestic double in 2020.
For her country, Celin has represented Norway at all playing levels from under-16, making 21 full international appearances to date.
Celin Bizet:
"I'm very excited to take this next step in my career, and sign for such a great club as Manchester United. I cannot wait to pull on the famous red shirt and create winning moments in front of these wonderful fans."
Marc Skinner:
"Celin is an exciting, talented young player with lots and lots of potential. She suits exactly where we are trying to be as a team — we want young, hungry players, who can make a real difference. Celin is definitely one of those players of absolute quality and we are really looking forward to embedding her into our squad."
Everyone at Manchester United welcomes Celin to the football club and wishes her every success in red.