Vice President JD Vance has made fun of both Gavin Newsom and Mike Pence in an interview with Bill Maher. 

Vance was appearing on the liberal Maher's show to promote his new book, Communion, which is about his faith journey as a convert to Catholicism in adulthood.

The comic - a lapsed Catholic and an avowed atheist - suggested that his book was similar to Gavin Newsom's in how they were upfront about religion.

When asked if he would read Newsom's book, Vance joked: 'People bought my book is the difference.'

As both Maher and the audience howled, Vance attempted to play it off, asking: 'Sorry, was that mean?'

Newsom's memoir, Young Man in a Hurry, largely ignores politics, as the California governor focuses on the struggles of his parents' divorce, growing up with dyslexia, and working as a paper boy.

The Vice President was frequently willing to go along with the show's comedy, even when referencing his predecessor, Mike Pence. 

Vance seemed surprised that the arch-conservative Pence would go on Maher's show, before making a joke at Pence's expense. 

'What did you talk about with Mike Pence - sex, drugs and rock n' roll?'

The partisan audience roared with laughter and applauded Vance's play on Pence's stoic nature.

Maher, for his part, said Pence was 'a lot more human than I'd ever seen him.'

The pair also discussed their disagreements regarding ICE's conduct in US cities and whether or not the Iran deal is going to work and eliminate Tehran's nuclear program. 

Vance even agreed to come on Maher's Club Random podcast, though he said he wouldn't 'smoke weed' as guests traditionally have with Maher. 

Maher, however, appeared disappointed with Vance on the show's Overtime segment with other guests, Georgia Democrat Senator Raphael Warnock and comedian Larry Wilmore.

The host had told Vance that his vote was 'in play' for the 2028 election and with Vance a potential candidate, wanted him to say that he would concede the election.

Vance, however, repeated his belief that the 2020 election was rigged by big tech spreading misinformation.

Maher said: 'He's gonna get a big clap on the back from the boss tonight, he didn't go with me on anything. I'm sure he doesn't want to be in the dog house.'

Communion: Finding My Way Back to Faith, the follow-up to his 2016 best-seller Hillbilly Elegy, which turned him into a household name and put him on the political map. 

In just 10 years, Vance went from first-time author to Vice President.

Communion is largely about Vance's spiritual journey from Protestant to atheist to converted Catholic. 

It comes as Trump has been publicly floating who would be a better heir in 2028 - Vance or Secretary of State Marco Rubio, who ran against the President for the Republican nomination in 2016. 

Possible presidential candidates often write books ahead of launching their campaigns, with possible Democratic 2028 hopefuls, California Governor Gavin Newsom and Pennsylvania Governor Josh Shapiro, releasing books in recent months.

At the same time, sources told the Daily Mail that Vance may be rethinking what previously looked like a definite White House bid in two years. 

During an interview with CBS Sunday Morning promoting the book, Vance said he would wait to discuss 2028 with Usha, who is pregnant with the couple's fourth child, until after the November midterms. 

In 2022, Trump - at the time an ex-President - launched his third bid for the White House just a week after the midterms wrapped up, the earliest announcement in presidential history.