Robert Downey Jr
Robert Downey Jr plays Iron Man in Marvel Cinematic Universe Ian Gavan/Getty Images

Robert Downey Jr has the "kindest heart in Hollywood", as the Iron Man actor recently face-timed with cancer patient Ryan Wilcox, proving once-and-for-all he is the superhero, not only in movies, but in real life, too.

Downey checked in on Ryan, an 18-year-old boy battling AML(Myelodysplastic Syndrome), a secondary cancer, for years now. A photo was uploaded to a Facebook page dedicated to Ryan Wilcox, featuring the Iron Man actor face-timing with the sick fan.

The post said, "So this just happened...just in case you all needed a smile. Ryan and his pal Robert Downey Jr. face timing. This definitely made us smile BIG. Joy is a very powerful medicine. Thank you of the kindest hearts in Hollywood. ‪#‎IronMan ‪#‎RyanStrong ‪#‎GodSpeed ‪#‎IBelieve". Marvel actors Downey Jr., Gwyneth Paltrow, and Chris Evans paid a visit to Ryan earlier in May, 2016.

So this just happened...just in case you all needed a smile. Ryan and his pal Robert Downey Jr. facetiming. This...

Posted by Team Ryan, Stay Strong and FIGHT On on Thursday, August 18, 2016

According to a report in Comic Book, their conversation was a simple affair, with no press or publicists involved. Robert wanted to check in on Ryan, and see how he was doing, and the chat surely meant a lot to the long time Marvel fan.

Downey's move was lauded by his fans on facebook, with one user commenting , "This fills up my heart for Ryan and for you. Kind hearted, compassionate hero! Thank you Robert Downey, Jr. for bringing a smile to all of us today but especially for the joy you've given Ryan and his family.

Another user said, "Ryan stay strong! Mr Downey you sir are a class act! Thank you."

Previously, Gwyneth Paltrow took to social media to post an image of Evans and Downey smiling alongside Wilcox. She captioned the image as, "Today @ryanwilcox0303 got a little surprise. Thank you to the incredible #chrisevans and my better work half @robertdowneyjr for being the men you both are. And thank you to the Wilcox family for your hospitality!"