Julia Roberts gushes over 'dreamy' Gaslit co-star Sean Penn

Julia Roberts loves to spend time with her "dreamy" Gaslit co-star Sean Penn.

During an appearance on The Late Show with Stephen Colbert on Monday night, the Oscar-winning actress explained that she has known the actor/activist since she was a teenager in New York City, but the new political thriller series marks the first time they have worked together.

Contrary to his serious persona, Julia insisted Sean is always "nice and sweet".

"We are very good friends. He is really one of my dearest (friends)," she said, adding that he is "dreamy" to hang out with. "Don't tell anybody. He would be so cross with me to say that but yeah, he's a dream. He cares so deeply about film and character and people and humanity, he's just... he's incredible."

Julia went on to note that she was impressed with the way Sean put up with the bodysuit and heavy make-up for his transformation into former U.S. Attorney General John N. Mitchell for Gaslit.

"He had so much patience getting all of this make-up done. And it was, you know, he had a bodysuit and this whole thing. And it would be so hot," the star recalled. "I am in these fake furs and my wig and my bodysuit (to play Martha Mitchell), it's so hot, I'm so itchy. (I was thinking), 'Oh God, somebody take my coat!' And he just was rock steady, all his stuff on. He would just sit there."

Gaslit, which delves into several untold stories related to the Watergate scandal in the early 1970s, is set to premiere on Starz on 24 April.