"Iron Man, if you see this, I really, really need your help."

Those are the words Aaron Hunter chose to reach out to Robert Downey Jr.

The little kid has Rapid-Onset Obesity with Hypothalamic Dysfunction, Hypoventilation and Autonomic Dysregulation (ROHHAD).

He wanted to reach out to Iron Man to help him raise money and awareness for ROHHAD so he put up this video.

That was in January last year.

It took a while for the video to reach Robert, who promptly facetimed with Aaron.

Aaron called it "the best day of his whole life."

But that wasn't all...

Earlier this month, Robert went down to meet Aaron in person and even shared a photo on his Instagram.

Obviously, Aaron was over the moon!

"We have never seen Aaron this happy until now. His big heart is full of hope and the best is yet to come with the help this will bring all of the children fighting ROHHAD as Robert fulfils Aarons wish in full," said Aaron's mother.

And that's not all...

Robert is now running a campaign on his charity's website where winners will get tickets to the Avengers: Infinity War premiere.

He gave more details about the contest in this video:

'Take that suit off and what are you,' Captain America once asked Iron Man. 

His badass reply was: 'Genius, billionaire, playboy, philanthropist.'

Well, he can add 'nice guy' to that list.