Rooney took part in a Samsung Q&A on Wednesday.
Asked by one fan: "If you could bring any player from the Galaxy team to Manchester United, which player would it be?"
Rooney replied: "Probably Cristiano!"
He also claims Ronaldo and Paul Scholes are the best players he has played alongside.
However, the 28-year-old was unable to separate the two and said: "The best player I've ever played with is between two - Cristiano Ronaldo and Paul Scholes. Scholesy controlled the game and passed the ball around but in terms of winning games - Cristiano Ronaldo."