Iron Man Robert Downey Jr surprises 7-year-old boy with new bionic arm

Robert Downey Jr reprised his role as Marvel superhero Iron Man to personally deliver a bionic limb to a child with a partially developed arm.

Seven-year-old Alex, who likes superheros and riding his bike, was the lucky recipient of the gift as part of the Collective Project - the brainchild of college student Albert Manero.

Manero, who builds and donates low-cost, 3D-printed bionic limbs to kids around the world, was able to pull off the stunt with the help of a leading bionics expert.

Alex appeared remarkably chilled out about meeting Downey Jr, whose Iron Man character employs numerous robotic limbs.

Alex and Downey Jr each had a robotic arm to try on. Credit: YouTube/officevideos
Alex tries out his new, hi-tech limb. Credit: YouTube/officevideos
Bionic fist-bump. Credit: YouTube/officevideos

Downey Jr seemed almost as thrilled as Alex about the meeting, tweeting several photos of the moment.