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When Alex went to pick up his new bionic arm, he had no idea he'd be getting it from a genius, billionaire, playboy philanthropist.

The 7-year-old was born with a partially-developed right arm and was selected by Albert Manero – a University of Central Florida student who creates and donates bionic limbs using 3D printers – to receive one of his latest creations.

But as he went to get it, he was met by none other than Robert Downey Jr., who presented a very familiar looking arm to Alex while in character as Tony Stark.

Iron Man certainly proved he has a heart – and this video will melt yours.