Anderson joined United from Porto for around £17million.
He said: “This is a dream move, one I could not reject. The chance to play with Cristiano Ronaldo was enough to bring me to United — he is a worldwide star.
“I can’t wait to set up a goal for him. He is a spectacular player who has improved so much at United and I want to do the same.
“I will be proud to play alongside him and prove that Brazilians can flourish in the Premier League. I will be a strong player.
“The aim is to win the title — and stop Chelsea winning it. I can’t wait.”