The Make-A-Wish Foundation transformed nine-year old Domenic Pace with cystic fibrosis into Iron Boy for a day, so he could embark on a mission to save his city from Ultron.

The South Wales Police Department cooperated with Make-A-Wish for the event, which saw Pace enlisted on a mission -- as Iron Boy -- to save reporter Hope Joy from Ultron's henchman.

The adventure culminated in a one-on-one face-off with Ultron on the steps of the Sydney Opera House -- in which Pace saved the Australian city from the android's destruction.

"Iron Man" actor Robert Downey Jr. cheered Domenic on in a tweet:

Sent a very special boy on a top secret mission today. Go get 'em, Domenic! #IronBoyAU @MakeAWishAust- Robert Downey Jr (@RobertDowneyJr) February 11, 2016

Downey Jr. also released the following video, where he inducts Domenic into the Avengers as an honorary member.

"I hear you've had quite the day. It's hard work saving the world, isn't it," Downey Jr. said in the video. "Iron Man loves you."

(via Nine News Sydney)