Appearing on Friends was a career-altering opportunity. However, for the actors that did take part, it was at times a very nervous experience, especially given the chemistry of the main cast. The likes of Jennifer Coolidge admitted to keeping a low profile during their time on the show, given how tight the main cast was.

As we'll reveal in the following, Tom Selleck's experience on the show was also one that had some elevated levels of anxiety. Although Selleck was beloved in his role, he was very nervous behind the scenes.

We're going to take a closer look at his time on the show, and how Selleck was received by his co-stars, including

Jennifer Aniston. Although Jen wasn't always complimentary towards the guest-stars, she had major praise for Selleck.

Tom Selleck Was Extremely Nervous Stepping In On Friends

Among Tom Selleck's most memorable roles will always include his time on Friends as Dr. Richard Burke. Although Selleck does have fond memories of his time on the show, he was extremely nervous at the start. This was especially true given that the cast already had tremendous chemistry among one another early on.

"I try to relax the new actors because that's really hard, to come on a show where everybody's up to speed. It's like when I did Friends," he said. "They were up to speed," Selleck revealed alongside Kelly Clarkson.

Selleck would go on to admit that his table reads weren't great, and that the pressure of the role intensified given that he didn't have a background on sitcoms at the time.

"I was scared to death," he said. "I had done Taxi a long time before, but I hadn't done a sitcom. And so, I was really nervous."

Tom was able to get through it, and he credited Courteney Cox as a major help along the way behind the scenes.

"Courteney helped a lot. Courteney's a big help. But that group's an incredible group of friends. They obviously became friends in life as well as on the show. And it shows. It was a wonderful place to work."

Although Tom had mixed feelings about his time on the series, Jennifer Aniston felt completely different. She had nothing but praise for the actor and his involvement on the series.

Jennifer Aniston Praised Tom Selleck And His Behavior With The Cast Behind The Scenes

Behind the scenes, Jennifer Aniston had major praise for Tom Selleck.

Speaking alongside Howard Stern, she praised her co-star and that way he treated others on the sitcom.

"Tom has an angel's halo over his head, it's just a permanent halo over Tom's head," Aniston said about her experience alongside the actor.

During her interview on Hot Ones, Courteney Cox also had fond memories of her time alongside Selleck, calling him the best boyfriend she had on the show.

"Well, Tom Selleck was the nicest, and the tallest. Jon Favreau is the best director, [but] he wasn't directing then."

It clearly was a positive atmosphere on the set of Friends. However, Jennifer Aniston wasn't praising every guest-star and in truth, she felt the complete opposite about a certain cameo during the earlier seasons.

Jennifer Aniston Wasn't Complimentary Towards Every Guest-Star, Especially Fisher Stevens During The Earlier Seasons

Speaking alongside Howard Stern, Jennifer Aniston did pinpoint a certain guest-star, and how they thought they were above the show during the early seasons, prior to Friends' massive fame.

Aniston recalled, "I remember when we were doing a network run-through, the network and the producers would just laugh," she explained. "And this person would be like, 'Listen to them, just laughing at their own jokes.

So stupid, not even funny."

She continued, "It was just like, 'What are you doing here? Your attitude, this is not what we're all about. This is a wonderful, warm place to be, and you're coming into our home and just s*** on it.'"

The person Aniston was referring to is Fisher Stevens. The actor would comment on Aniston's claims, not denying her claims. Stevens would reveal that his mood soured after his script was changed right before the shoot, and wasn't as appealing as the first one.

"Because that's what sitcoms did," he said. "And I didn't know that. I was kind of an a******, I have to admit.

"What do you mean? So I have to relearn lines that you've written that are worse than what you'd originally written?' Yeah, I was a ****."

Stevens would go on to apologize for his conduct. "I've rarely seen any of those people on Friends again, but I'm sure if you asked them about me, they would go, 'What a New York snob.' I'm sorry, guys. I'm sorry. I apologize. I was bad, I was wrong."

To no surprise, he wasn't welcomed back to the show following his brief cameo.