In a heartwarming video posted on his Facebook, Downey Jr who plays Tony Stark in the superhero franchise, gifted the arm to the adorable boy named Alex, reported Us magazine.
"Had the absolute privilege of presenting a brand spanking new 3D-printed bionic Iron Man arm to Alex, the most dapper 7-year-old I've ever met," the 49-year-old actor shared on Facebook.
"Special thanks to Albert Manero, OneNote, and #CollectiveProject for their work making artificial limbs like this more affordable for families with kids who want to show the playground how badass they are," he added, along with a link to Limbitless Solution's site.