Bei/Shutterstock Jim Carrey and Courteney Cox in 1994
The 57-year-old actress appeared on Howard Stern's SiriusXM show on Wednesday alongside her fellow Friends alums Jennifer Aniston and Lisa Kudrow, where she dished on making 1994's Ace Ventura: Pet Detective.
"He was so funny; it was just about cracking up all the time," said Cox of Carrey, 59. "I remember when we first rehearsed, he was just playing it straighter. And then he turned it on when we started filming and I thought, 'Oh my God, he's the funniest person.' "
Carrey and Cox - who played Ace Ventura and Melissa Robinson, respectively, in the slapstick comedy - "became really good friends" according to the actress, and her costar "cracked [her] up the entire time."
When asked by Stern, 67, whether non-platonic sparks flew, she admitted, "There was a crush for sure."
Never miss a story - sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human-interest stories.
Morgan Creek International/Kobal/Shutterstock Jim Carrey and Courteney Cox in Ace Ventura: Pet Detective (1994)
"But nothing romantic?" Stern asked, to which Cox deflected in response with a laugh, "I don't … I'm going to go to the bathroom."
"The reason I ask that is there are these two talented people," offered the host. "I can't see how that wouldn't happen. If I was around you, I would have at least tried."
In a 1994 interview surrounding the film, Cox previously said that Carrey's humor begins as "he rolls out of bed" and is "in him 24 hours a day."
"He has another side to him, believe me, that's very serious and actually really intense. But [the comedy] is there all the time," she added.
Ron Galella/Getty Courteney Cox and Jim Carrey in 1994
RELATED VIDEO: The Guys Behind Dumb and Dumber Pick Their Favorite Jim Carrey Film
Aniston, 52, also chatted with Stern about her love life of years past, insisting that there was no awkwardness at all between herself and ex-husband Brad Pitt.
"It was absolutely fun," she said of having reunited with Pitt, 57, back in September for a live table reading of Fast Times at Ridgemont High. "Brad and I are buddies, we're friends."
The pair played romantic interests in the star-studded virtual reading, as Aniston portrayed Linda (originally played by Phoebe Cates in the 1982 teen movie) and Pitt read for Brad (originally played by Judge Reinhold).
"And we speak, and there's no oddness at all, except for everyone that probably watched it and was wanting there to be, or assumed there to be," Aniston continued. "We had fun, and it was for a great cause, [Sean Penn's community-relief nonprofit] CORE."