Actor Robert Downey Jr. made a child's day when he delivered an "Iron Man" bionic arm to him as Tony Stark in a touching video published Thursday.

The 3D-printed prosthetic was designed by University of Central Florida mechanical engineering doctoral student Alberto Manero, and delivered to a seven-year-old named Alex.

Alex was born with a partially developed right arm, and is one of the many children around the world who have been helped by Manero's Limbitless Solutions. The "Iron Man" themed limb took over 40 hours to design, build, and paint, and looks surprisingly close to the arm worn by the Marvel superhero.

"A huge thank you to Robert Downey Jr. for getting involved and helping raise awareness for the great work Limbitless Solutions is doing," the company wrote on Facebook. "Coming together like this is what the ‪#‎CollectiveProject is all about. Robert, it looks like you might have some competition for your next movie."

While traditional prostheses can cost $40,000, the team at Limbitless can create them for $80-$400, and deliver them to families at no cost.

"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," Downey wrote 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 bad[expletive] they are."

Limbitless Solution's #CollectiveProject is seeking 3D designers and artists to add more illustrations to the company's catalog of designs for bionic arms. They also accept donations for their project with support from Microsoft's OneNote.

Watch Downey's meeting with Alex in the heartwarming video above.