David Tennant isn't an actor who's afraid of chatting and speculating about the future of BBC sci-fi series 'Doctor Who'; after all, he did serve as the 10th iteration of the character, bringing his own unique skills to the show and becoming an instant fan-favourite version of the Doctor.

David Tennant doesn't think Olivia Colman has time for Doctor WhoDavid Tennant doesn't think Olivia Colman has time for Doctor Who

For some time, fans of the show have known that this current series of 'Doctor Who' will be Peter Capaldi's final outing in the titular role, with showrunner Steven Moffat also stepping down at the end of the series. Whilst we know 'Broadchurch' creator Chris Chibnall will be taking over from Moffat, the actor stepping into the shoes of the Doctor is still to be confirmed.

One of the names on everybody's lips is Olivia Colman; a woman who's no stranger to working with Chibnall following her extensive work leading the three series of ITV crime drama 'Broadchurch', alongside Tennant. The latter however doesn't think Colman will be taking on the job.

"I really don't think that's a serious option," Tennant said to EW when asked if his fellow 'Broadchurch' star could become the next Doctor. "Olivia is busier than any other actor on Earth. I don't think she'd be able to suddenly take four years off to go to Cardiff. I don't think her schedule would really allow it whether she wanted it or not."

It's true that Colman is working with an incredibly full slate at the moment, with the 'Watership Down' mini-series, 'Murder on the Orient Express' film and her role as Queen Anne in upcoming flick 'The Favourite' just some of what she has in the pipeline right now.

Whether she's live on screen in her roles or serving as a voice actor, Colman has quickly become one of the most recognisable faces on British television, with her incredible talents earning her praise from critics and the general public. Exactly where we see her next remains to be seen, but if Tennant knows anything about his friend taking on the role of the Doctor and becoming the first female Doctor Who, he's certainly doing a good job of hiding it.

More: Will Kris Marshall Take Over Peter Capaldi On 'Doctor Who'?

The current series of 'Doctor Who' comes to an end this coming Saturday, on July 1 on BBC One.