Jennifer Aniston had worked years on the set of the hit TV show "Friends" and she knows a thing or two about how their special guests react on set while their filming a specific scene.

The "Just Go With It" star sat down with Sebastian Stan in the latest issue of Variety's "Actors on Actors" where they discussed things they have experienced in their careers as Hollywood Actors.

Aniston explained why celebrity guests on the late 90s TV sitcom were "terrified" when they star in the show.

"Every actor who was a film actor who came onto our show, they were terrified. It was like, 'Who are these people laughing at what I'm saying?'" the 53-year-old actress revealed. (via ET Online)

The reason why they were scared is that the show had an "audience" on set.

According to Showbiz Cheat Sheet, the show was indeed filmed in front of a live audience and it helped the show in many ways.

Usual sitcoms use laugh tracks, but "Friends" opted to have a live audience to receive genuine reactions.

In addition, having people watch the actors and react genuinely helped writers realize what jokes or punchlines worked on the spot.

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"To work in front of a crowd is great because it's the ultimate sound board. If you say the joke in the scene and you hear crickets, it's not funny," Matt LeBlack, who played Joey Tribbiani on the show, told Jimmy Kimmel.

Although Aniston, who played the role of Rachel Green, did not reveal which guests were terrified filming on set, Tom Selleck explained his experience in a previous interview.

In an appearance on "The Kelly Clarkson Show," the actor said he was "scared to death" as the everybody on the show is "up to speed."

Lucky for him, Courteney Cox gave him a helping hand.

He then commended the cast for being an "incredible group of friends" as their friendship continued blossoming over the years after the show, meaning it was a "wonderful place to work."

Elsewhere in the "Actors on Actors" interview, Aniston also recalled the successful reunion, saying she did not expect it to be very emotional.

Initially, they had an idea that reuniting with each other would be "so fun," but when they went back on set, everything they left was exactly the same and it felt like time traveling.

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