Kidman and Watts have been friends for more than 30 years

Kidman joked that she had to "beg" Schreiber to "marry" her. The Ray Donovan actor, meanwhile, said, "I heard a story that you asked Naomi first if it was okay." Kidman confirmed that she did, to which Schreiber replied: "Isn't that amazing? That's how close they are."

Kidman and Watts' friendship goes back more than 30 years. When presenting Kidman with the AFI Life Achievement Award in April, Watts shared that the pair met in the 1980s at an audition for a swimsuit commercial.

While waiting to find out who got the role, they talked. "We covered everything, what movies we loved, what friends we had in common, our parents, schools, parties, boyfriends, teenage stuff," Watts recalled.

When they were told they were free to go after not getting the role, Kidman offered to cover a taxi ride home for Watts, who had missed the bus. She called Kidman "the most generous person."

"She's opened up her homes to me. She's made me feel like part of her family. She was like the sister I'd never had," Watts added.

The official synopsis for The Perfect Couple reads: "Amelia Sacks is about to marry into one of the wealthiest families on Nantucket. Her disapproving future mother-in-law, famous novelist Greer Garrison Winbury [Kidman], has spared no expense in planning what promises to be the premiere wedding of the season -- until a body turns up on the beach.

"As secrets come to light, the stage is set for a real-life investigation that feels plucked from the pages of one of Greer's novels," the synopsis continues. "Suddenly, everyone is a suspect."