The Portuguese completed his return to the club last month, 12 years after leaving to join Real Madrid.
Man United's media channel released a video of him stepping onto the Old Trafford pitch for the first time since completing the transfer.
And after taking in his new home, he simply to fans: "I'm home."
Ronaldo is gearing up for his second debut for Man United, which could happen on Saturday as they take on Newcastle at Old Trafford.
His acquisition will be a huge boost for their hopes of getting back to the top.
"This is why I am here," he said in an interview with the club's official website. "I am not here for a vacation.
"Before was good, winning important things and I wore the shirt before, many years ago, but I am here to win again.
"I am capable, me and my team-mates. I am ready to go, I am ready to go. It is a good chance for me, for the supporters, for the club, to get one step ahead.
"I am ready and I think I will be a huge thing in the next three or four years."
And Wayne Rooney is very optimistic about what his former teammate can bring to the current Man United squad.
Asked what impact Ronaldo could have, Rooney told talkSPORT: "An enormous one, I think he's still one of the best players in the world.
"I think we've seen in the game against Ireland that's what he does, last couple of minutes he scores two goals, two great headers, so he can have a massive impact on this league."
talkSPORT will be bang across Ronaldo's potential second Man United debut on Saturday afternoon on the radio, online and on social media.
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