Jemaine Clement has taken on a celebrity Donald Trump supporter in an explosive Twitter row.

The Flight of the Conchords star's social media exchange with the Happy Days actor, an early and unwavering Trump supporter, became heated today.

In one of a multitude of tweets, Clement said: "Scott Baio supporting @realDonaldTrump is the worst Italian-German pairing since 1945."

Scott Baio supporting @realDonaldTrump is the worst Italian-German pairing since 1945

— Jemaine Clement (@AJemaineClement) January 30, 2017

Baio then labelled him an "angry snowflake" - a reference to a term Trump supporters have labelled his opponents.

At one point, Clements said: "Sit on it, Chachi" - a reference to Baio's 1980s Happy Days character.

You're an angry Snowflake!

— Scott Baio (@ScottBaio) January 30, 2017

He responded with: "That's all you've got Kiwi? Bet you live with a lot of sheep."

Baio also shared a close-up photo of Clement and said: "It's nice to be thin & have all of my hair at 56. WTF happened to you? Born in 1974. Yeah OK."

He replied: "Bless you, Chachi. I hope your long battle with puberty is over by the time you hit 60."

He also shared a picture of Baio posing with Trump, alongside a picture of Adolf Hitler with leader of the Italian Fascist Party Benito Mussolini and said: "Were you guys going for this? "Let's do a Germans and Italians back together again thing!"

Sit on it, Chachi.

— Jemaine Clement (@AJemaineClement) January 30, 2017

Baio responded with: "I stand with Israel. As does President @realDonaldTrump. Keep sucking the tit of @CNN. Worry about your country."

Baio has supported Trump's campaign throughout.

He claims he was attacked on his way to the Liberty Ball following Trump's inauguration on January 20.

That's all you've got Kiwi? Bet you live with a lot of sheep.

— Scott Baio (@ScottBaio) January 30, 2017

A protester reportedly labelled him a 'f***ing fascist', and lunged at him.

Baio last year spoke at the opening night of the Republican National Convention.

In an interview on Fox last year, Baio described President Barack Obama as being "either dumb, a Muslim, or a Muslim sympathiser, and I don't think he's dumb".

It's nice to be thin & have all of my hair at 56. WTF happened to you? Born in 1974. Yeah OK. @AJemaineClement

— Scott Baio (@ScottBaio) January 30, 2017

He questioned what the "liberal endgame is" and added: "Is it to totally eliminate the United States as it was created and founded and the way it is now?"

In December, he accused Nancy Mack, the wife of Chad Smith, drummer for Red Hot Chili Peppers, of assaulting him at their children's school function after she cursed him over supporting Trump.

Mack has said she was trying to show him how Trump hugs women and has denied any physical aggression.

Were you guys going for this? "Let's do a Germans and Italians back together again thing!"

— Jemaine Clement (@AJemaineClement) January 30, 2017

I stand with Israel. As does President @realDonaldTrump. Keep sucking the tit of @CNN.Worry about your country.

— Scott Baio (@ScottBaio) January 30, 2017