Donald Trump attacks "whimpering" Jimmy Fallon over the TV host's recent comments.

In yet another Twitter rant, US President Donald Trump has slammed The Tonight Show host Jimmy Fallon for admitting he regrets his 2016 interview with Trump on the talk show.

In the tweet, Trump described Fallon as “whimpering” and told him to “be a man”.

.@jimmyfallon is now whimpering to all that he did the famous “hair show” with me (where he seriously messed up my hair), & that he would have now done it differently because it is said to have “humanized” me-he is taking heat. He called & said “monster ratings.” Be a man Jimmy!

— Donald J. Trump (@realDonaldTrump) June 25, 2018

In an interview with The Hollywood Reporter last week, Fallon admitted that he regretted his Tonight Show interview with Trump during the presidential campaign, where he playfully messed with Trump’s hair.

“I did not do it to ‘normalise’ him or to say I believe in his political beliefs or any of that stuff,” he said.

At the time, critics and even other comedians slammed the interview, calling it ‘the biggest mistake of Fallon’s career’, claiming the interview could sway viewers who were on the fence about Trump.

“If Jimmy Fallon had any credibility left as a thinking comedian with a point of view, he lost the last shred of it last night,” TV critic Sonia Saraiya wrote for Variety at the time.

You can watch the original clip here:

On social media, people also criticised Fallon for not being as political as other late-night talk show hosts – while other hosts questioned the presidential candidate’s controversial ideas, Fallon discussed menial topics and joked with Trump instead.

Discussing the backlash with The Hollywood Reporter, Fallon said: “It was definitely a down time.”

“I’m sorry. I don’t want to make anyone angry – I never do and I never will. It’s all in the fun of the show. I made a mistake. I’m sorry if I made anyone mad. And, looking back, I would do it differently,” Fallon added.

Fallon has now responded to Trump’s tweet, revealing that he will be making a donation to RAICES – a non-profit designed to benefit immigrants and their children – in Donald Trump’s name.