It was a different Sean Spicer who paid a visit to US late night show Jimmy Kimmel Live.

On Thursday night, a smiling Spicer was a marked contrast to the six hot-tempered months he spent as White House Press Secretary, conducting volatile news conferences that were given added heat thanks to Melissa McCarthy's unsparing impersonation of him on Saturday Night Live.

"It was kinda funny," Spicer giggled about McCarthy's impressions, which scored the actress an Emmy earlier this week.

"That cost me a lot of money in therapy," he joked. "I don't think [Trump] found as much humour in it as others."

It was Spicer's first television appearance since resigning from the Trump Administration in July from what Kimmel joked was his hit reality show, 'I'm the Press Secretary - Get Me Out of Here.'

He took Kimmel's ribbing in much better spirits than the grilling the White House press corps dished out.

"A lot of these members of the press were your friends, right?" Kimmel asked.

"WERE, yeah," replied Spicer, chuckling.

Kimmel reminded him of how his tenure began: awkwardly backing up Republican President Donald Trump's claim that his inauguration crowd was the biggest ever, when photographic evidence proved otherwise.

"Why is he so concerned with size?" asked Kimmel. "Have you ever seen the president naked?"

"I have not," Spicer replied good-naturedly.

But even if Spicer knew Trump's crowd wasn't larger, Kimmel pressed on, his job as press secretary obliged him to say that it was.

"Your job as press secretary is to represent the president's voice," Spicer explained. "Whether you agree or not is not your job."

"And then you have to march out there and go, 'He had a bigger crowd, everybody'," Kimmel laughed.

"As I said, he's the president; he decides," Spicer said.

"I understand," Kimmel acknowledged.

"And that's what you sign up to do," Spicer concluded.

Kimmel swung back around to the incident one more time, as they discussed Spicer's relationship with the press, showing a video of the time ABC's Jonathan Karl asked if Spicer intended to always tell the truth. Spicer was not pleased with that remark.

"To get up there and question, on day one, my integrity, I think was not something that I anticipated," he said.

"Yeah, well, I'm sure. Although when you brought that crowd size thing out, you opened this terrible Pandora's box," Kimmel countered. "You think that got you off to kind of a bad start with the press corps?"

"I don't think it was probably the best start, no," Spicer said, smiling.

At Kimmel's urging, Spicer tried to account for the tension that prevailed between him and the press.

"Some of us who worked very hard to get (Trump) elected felt as though a lot of folks, in the media particularly, constantly sought to undermine the validity of that election," Spicer said. "So you to have to understand it sometimes from that perspective."

If Kimmel thought Spicer would dish dirt on Trump, he was disappointed.

"Sean, you don't work there anymore," Kimmel jokingly egged him on. "You don't have to worry about him. We can protect you here."

But Spicer remained resolute in his defence of Trump, declaring at one point: "He's a good man that really cares about this country."

Kimmel also asked if Spicer celebrated after the now-infamous New Yorker interview that led to the extremely swift departure of his replacement Anthony Scaramucci. Spicer insisted there was no schadenfreude.

"I don't think it's right to relish in someone else's problems," Spicer said. "But again, I think it proved my point that to do this job, it's one in which you have to have the proper background."

Kimmel interrupted: "I imagine you high-fiving everyone." Spicer just laughed.

AP, Washington Post, Fairfax Media