Robert Downey Jr has defended Marvel co-star Chris Pratt after the actor was criticised on social media.

A Twitter user posted a picture of Pratt and other stars named Chris – Pine, Evans and Hemsworth – along with the caption: “One has to go.”

A majority of the comments appeared to be in favour of jettisoning Pratt.

Many cited Pratt allegedly being a Donald Trump supporter while others said he attends a church with anti-LGBT views. He has previously denied the latter claim.

Downey Jr, who plays Iron Man in the Marvel films, has now defended Pratt, who portrays Star-Lord.

Alongside a picture of the pair together, Downey Jr said: “What a world… The ‘sinless’ are casting stones at my brother, Chris Pratt… A real Christian who lives by principle, has never demonstrated anything but positivity and gratitude…

“AND he just married into a family that makes space for civil discourse and (just plain fact) INSISTS on service as the highest value. If you take issue with Chris,,, I’ve got a novel idea.

“Delete your social media accounts, sit with your OWN defects of character, work on THEM, then celebrate your humanness…”

Downey Jr added the hashtag #gotyerbackbackback.

He was not the only star to defend Pratt. Mark Ruffalo, who plays Hulk in the Marvel movies, said: “You all, @prattprattpratt is as solid a man there is. I know him personally, and instead of casting aspersions, look at how he lives his life.

“He is just not overtly political as a rule. This is a distraction. Let’s keep our eyes on the prize, friends. We are so close now.”

And James Gunn, who directed Pratt in 2014’s Guardians Of The Galaxy, tweeted: “Sorry. Just finding out about this nonsense. @prattprattpratt is the best dude in the world. I’ve spent hours & hours sharing my deepest truths with this man, as he has with me. Please stop assuming what he believes, politically or in any other way, because he’s a Christian.”

Pratt’s wife, Katherine Schwarzenegger, had earlier criticised the “mean” social media posts comparing the stars named Chris.

“Is this really what we need?” Schwarzenegger she wrote. “There’s so much going on in the world and people struggling in so many ways. Being mean is so yesterday. There’s enough room to love all these guys. Love is what we all need not meanness and bullying. Let’s try that.”