The Hills star, 39, slammed the Friends actress after he was asked who he thought was the rudest celebrity.

Pratt responded to the fan question on TikTok: “Oh that’s easy. Phoebe from Friends; hands down one of the worst humans I’ve ever come into contact with, by far.”

He refused to elaborate, saying he would “think” about telling his story if the video got more than one million views.

Pratt later clarified his statements in another TikTok he filmed while on a beach.

“The year was 2009 and [wife] Heidi [Montag] and I were invited to our first elite A-list party. It was clear when we got there, no-one wanted us there,” he started.

“It was almost like we were filming for Punk’d and a camera was going to pop up, but Heidi and I didn’t care as there was delicious food and an open bar.”

He then opened up on the ill-fated interaction with Kudrow.

“As we were sitting there consuming a little caviar, Phoebe [Lisa] approaches, which was a little shocking as no-one had spoken to us at all at the party,” Pratt continued.

“Right in front of me she tells Heidi that she needs to get away from me as fast as possible because I’m going to murder Heidi and that I have the eyes of a serial killer.”

He added: “Heidi waits to see if this a joke, maybe this is a hidden camera party. But no laughs, she [Lisa] just walks away.

“That right there as the rudest moment I’ve ever encountered with a human being”.

Many fans reacted in shock to Pratt’s story and even Real Housewives Of New York’s Bethenny Frankel got involved, describing how she also had a moment with Kudrow on her podcast.

“That’s crazy,” Frankel commented. “She was on my talk show and I had a crazy experience also.”

She later explained what happened between the pair.

“When [Lisa] was on my talk show, she stood out as the person who wanted to be there least of anybody the entire run,” Frankel said on TikTok.

“It was like I walked up to her at the supermarket, and she’d be like: ‘What?! You’re coming up to me in the frozen food section.’

“I was asking her basic questions, and you could tell she didn’t wanna be there, which does make two of us.”

Frankel added she believed Kudrow was a good person but “she didn’t wanna be interviewed, which gets in the way of an interview.”

Kudrow’s fans dismissed the reality stars’ claims and defended the actress on Twitter.

“Lisa Kudrow clearly not being into interviewed by Bethany & telling Heidi to leave Spencer Pratt cause he has serial killer eyes just shows that she has good taste, wrote one fan.

Another added: “Lisa Kudrow was rude to Spencer Pratt and I’m supposed to like her less for that?”

And a third said: “this is incredibly funny for lisa kudrow and incredibly embarrassing for spencer pratt lmao.”

Pratt and Montag carved out a career as one half of Speidi on The Hills.

The couple have competed as one entity on I’m A Celebrity… Get Me Out Of Here! , as well as the U.K. version of Celebrity Big Brother.

Montag is currently 27 weeks pregnant with their second child, having welcomed a son, Gunner, in 2017.

Newsweek has reached out to Kudrow for comment.