Robert Downey Jr. and Mark Ruffalo have leapt to the defence of Chris Pratt after he was branded the "worst Hollywood Chris"

Robert, 55, insisted his friend is a "real Christian" who always displays "positivity and gratitude", as well as praising Chris' wife Katherine Schwarzenegger and her famous family.

He wrote on Instagram alongside a photo of himself and 41-year-old Chris: "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."

The 'Iron Man' star urged those who "take issue" with the 'Guardians of the Galaxy' star to come off social media and work on their own "defects of character".

He added: "If you take issue with Chris,,, I’ve got a novel idea," Downey Jr. continued. "Delete your social media accounts, sit with your OWN defects of character, work on THEM, then celebrate your humanness... @prattprattpratt I #gotyerbackbackback.(sic)"

Mark insisted Chris is a "solid" man and shouldn't be singled out for his assumed conservative views.

He tweeted: "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.(sic)"

Director James Gunn hailed the star as the "best dude in the world".

He added: "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."

Zoe Saldana also defended her friend and insisted those who knew him really know his "heart and worth".

She wrote: "No matter how hard it gets, stick your chest out, keep your head up and handle it – Tupac. You got this @prattprattpratt. Your family, friends, colleagues & everyone who’s ever crossed paths with you knows your heart and your worth!(sic)"

Chris' wife, Katherine - who gave birth to their daughter Lyla in August - slammed the "meanness" of the survey.

She wrote: “Is this really what we need? 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."