The stars have known each other since they were in their early 20s
Nicole Kidman and Hugh Grant
Nicole Kidman and Hugh Grant in The Undoing
| Credit: Niko Tavernise/HBO

Nicole Kidman and Hugh Grant tapped into their longtime friendship in order to get into character for their upcoming HBO thriller series, The Undoing.

The show, which premieres Sunday, stars Kidman and Grant as a husband-and-wife pair embroiled in a Manhattan murder mystery.

In a recent joint interview with her costar, Kidman, 53, told Entertainment Tonight that the two were able to connect so well on screen "because we've known each other since we were in our early 20s."

"I feel very comfortable with him, and part of what it took for this to work is that this couple has to be very sort of comfortable and happy," she continued, asking Grant, "Would you not agree, Hugh?"

Nicole Kidman and Hugh Grant
Credit: Kevin Mazur/WireImage

"That was the aim," said Grant, 60. "We had to sort of establish all that in one episode before the rug was pulled from under the feet of this adorable couple."

"You know, Nicole's a laugh," he continued, playfully teasing that the Big Little Lies star is "a gossip, which I love. I can get stuff out of her."

"Well, you gossip about yourself, which I like," he clarified. "I like all the dirt."

"I do," Kidman acknowledged. "I'll answer questions about myself."

The Undoing is the first time Grant and Kidman are appearing on screen together — though Kidman recently admitted to wanting Julia Roberts' role opposite Grant in Notting Hill.

In a recent conversation with Marie Claire, Kidman revealed that she had her heart set on playing his love interest Anna Scott in the 1999 romantic comedy, and that she also almost ended up in Grant's 2003 ensemble holiday flick Love, Actually.

"I really wanted the role that Julia Roberts played in Notting Hill," she said. "But I wasn't well known enough, and I wasn't talented enough."

The Undoing premieres Sunday at 9 p.m. ET on HBO.