'Crown' star Matt Smith on who should play Meghan Markle

That's if Netflix's popular drama "The Crown" holds on for several more seasons.

The show's stars, Claire Foy and Matt Smith, sat down with Andy Cohen on Thursday night's "Watch What Happens Live" on Bravo and seemed delighted when a caller asked how they felt about Markle's engagement to Prince Harry and who they thought should play the couple on the series.

"The thing is they're so young, aren't they?" said Foy, who plays Queen Elizabeth II. "And they're probably not going to be on the show for another five years, so we're going to have to choose someone who's about 11 or 12."

Smith, who plays Prince Philip, then started fumbling for the name of a singer as possible casting, leading Cohen to believe he was thinking of Ed Sheeran for the role of Prince Harry.

"No, the singer who goes out with Justin Timberlake," Smith declared. "No, not Justin Timberlake -- Justin Bieber. Selena Gomez!"

"You love Selena Gomez," Foy said to him.

Foy said they are happy for the engaged royal couple.

"We love it that they're getting married," she said. "It's amazing. (Markle's) an actress, so that's great."

To which Smith quipped, "Well, she's not anymore. Her life's over."

The second season of "The Crown" starts Friday.