Mark Ruffalo slams Ellen DeGeneres over her friendship with George W. Bush

Most of Hollywood sided with Ellen DeGeneres after she spoke out in defence of her unlikely friendship with George W. Bush.

But not Mark Ruffalo.

The Avengers star shared a scathing tweet attacking The Ellen Show host, saying her friendly association with the former US president is morally wrong.

"Sorry, until George W. Bush is brought to justice for the crimes of the Iraq War, (including American-lead torture, Iraqi deaths & displacement, and the deep scars — emotional & otherwise — inflicted on our military that served his folly), we can't even begin to talk about kindness," the 51-year-old actor tweeted.

Ruffalo's criticism of DeGeneres is out of step with many Hollywood stars; celebrities including Reese Witherspoon, Jamie Foxx and Jennifer Garner have spoken out in support of her.

An image of Bush and DeGeneres sitting side-by-side and laughing at an NFL game sparked fierce debate online this week after being labelled "irresponsible and dangerous".

The photograph was taken of the friends and their respective spouses — Laura Bush and Portia de Rossi — in a stadium suite at a Dallas Cowboys game in Texas on Sunday.

It soon started circulating on social media which prompted many users to slam DeGeneres — a prominent gay, liberal and outspoken LGBTQI activist — for cozying up with the former Republican president, who once endorsed a constitutional amendment against same-sex marriage.

Mr Bush also entered the US into a war with Iraq and Afghanistan under the later-disproved belief that they possessed weapons of mass destruction.

Actor John Cusack went as far as to accuse DeGeneres of "normalising mass murderers" through association with Mr Bush.

Some critics noted that Mr Bush also lobbied for Supreme Court Justice Brett M. Kavanaugh, who faced multiple sexual misconduct allegations last year ahead of his confirmation. Mr Kavanaugh has denied the allegations.

On Tuesday, DeGeneres addressed the pair's unlikely friendship and the criticism surrounding it on her daytime talk show.

During the game, the broadcast showed a shot of the two laughing, and "people were upset," the star said.

"They thought, 'Why is a gay Hollywood liberal sitting next to a conservative Republican president?" DeGeneres continued.

"A lot of people were mad. And they did what people do when they're mad: they tweet.

"Here's the thing. I'm friends with George Bush," she explained of the former president, who was previously a guest on her show in 2017.

"In fact, I'm friends with a lot of people who don't share the same beliefs that I have."

"We're all different and I think we've forgotten that that's OK that we're all different.

"For instance, I wish people wouldn't wear fur. I don't like it, but I'm friends with people who wear fur," the host continued, adding, "But just because I don't agree with someone on everything doesn't mean that I'm not going to be friends with them. When I say be kind to one another, I don't mean only the people that think the same way that you do. I mean be kind to everyone."

Her monologue clocked four million views on Twitter in an advanced release on social media before it even aired on television.

A spokesman for Mr Bush told Fox News: "President and Mrs Bush really enjoyed being with Ellen and Portia (de Rossi) and appreciated Ellen's comments about respecting one another. They respect her."