Former New Jersey Governor Chris Christie has appeared in an interview with Stephen Colbert, downing shots of tequila as he boasted he'd have made a better president than Trump.

Christie appeared on Colbert's Late Show on Tuesday night, promoting his new book Let Me Finish, which details the backstabbing that led to his ejection from Trump's transition team.

After dropping out of the Republican presidential primary, Christie was the first major figure to endorse Trump's candidacy - but asked by Colbert if he'd have made a better president, the former governor replied simply: 'Yes.'

Colbert pressed Christie on his friendship with and support for Trump, saying, 'he'll throw anybody under the bus.'

'You think I don't know?' Christie replied to laughter from the audience. 'I got fired from the transition.'

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Christie (left) appeared on Colbert's Late Show on Tuesday night, promoting his new book Let Me Finish. The Republican former governor insisted on doing tequila shots with Colbert

Christie took three shots during the interview while Colbert reluctantly downed one

According to Colbert, Christie 'wanted a cocktail' for the interview, and so produced a bottle of tequila and two shot glasses.

The comedian pointed out that it was Casamigos, the 'liberal' tequila brand owned by George Clooney.

'I'll tell you something, if it gets me loaded, I don't care. Liberal, conservative, who cares,' Christie replied.

Christie took three shots through the course of the interview while Colbert reluctantly downed one.

In the interview, Christie said he had personally discussed the recent government shutdown with Trump in the White House residence, and urged him not to proceed without a strategy to end the standoff.

'The president blew it,' Christie said of the shutdown.

'I said this to him, like, listen, if you're going to do this, you better have an exit plan because sometimes in politics, things don't go the way you expect. And so if it doesn't go well in the first couple of days, you gotta have a way to get it back open,' Christie said.

'The president blew it,' Christie said of the shutdown, saying he had urged the President not to get into the standoff without a clear exit plan

He continued: 'I just said to him, 'It's okay. It's a power you have and if you want to do it but you have to have a plan so you accomplish something by it and then reopen it.' And I don't think, given that it went 35 days, we had a plan.'

Trump on Friday caved on his demand for $5.7 billion in border wall funding and reopened the government for three weeks without gaining anything from Congressional Democrats.

Despite it all, Christie was adamant that he did not regret backing Trump in the 2016 election.

Pressed on the issue, Christie pulled out the bottle of tequila and poured a shot before offering a fairly straightforward explanation.

'I made a decision at the time that he was going to win the nomination after I dropped out, and that I preferred him to Hillary Clinton,' Christie said.

'And that's why I made the decision. It wasn't a whole lot more complicated than that. And I still agree with what his policies are, more than I agree with Hillary Clinton's.'