The Egyptian has signed on the dotted line and moved to the Premier League.
Marmoush, who was impressive at Eintracht Frankfurt in the Bundesliga, wants to hit the ground running.
“I’m so happy to be here,” he told club media.
“Manchester City is one of the biggest clubs in the world over the past 10 years, so it was not a question.
“It is an honour the club showed an interest in me and now I’m here.
“The last two seasons have been great, but it is just the beginning for me.
“It’s a pleasure and an honour for me and my family to be representing Manchester City. It makes them happy; it makes me happy that my dreams are becoming a reality.
“I’m really excited and I can’t wait to meet my teammates, get on the pitch and start my journey with the club.”