David Tennant: Olivia Colman playing Doctor Who is not 'a serious option'

Ever since Peter Capaldi announced he will be leaving Doctor Who, some fans have been hoping Broadchurch‘s Olivia Colman will take on the titular role, which would make her the first actress to ever do so. Former Doctor and Colman’s Broadchurch costar David Tennant, though, isn’t so sure Colman stepping into the TARDIS is a real possibility.

“I really don’t think that’s a serious option,” says the Ducktales actor, who previously served as the tenth incarnation of the Doctor. “Olivia is busier than any other actor on Earth. I don’t think she’d be able to suddenly take four years to go to Cardiff. I don’t think her schedule would really allow it whether she wanted it or not.”

Colman isn’t the only actress up for consideration for the part. Tilda Swinton was the favorite for a while, as was Agent Carter‘s Haley Atwell, along with Colman’s Fleabag and Broadchurch costar Phoebe Waller-Bridge.

The idea of a female Doctor isn’t a new one. Not only does the current series of Doctor Who feature a female incarnation of the Master (nicknamed “Missy”) but the Doctor himself has commented on Time Lords being able to change gender, with the penultimate episode of the tenth season even seeing him say, “We’re the most civilized civilization in the universe. We’re billions of years beyond your petty human obsession with gender and its associated stereotypes.”

The Doctor Who season finale airs Saturday, July 1 at 9 p.m. ET on BBC America.