Peter Capaldi cried when announcing his Doctor Who exit

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“That was one of the funniest, most extraordinary moments I've ever had on air I think,” Whiley, who is presenting a special behind-the-scenes broadcast about Capaldi’s final episode next month, told RadioTimes.com.

“The fact that he chose to come on our show – and I remember saying to my producer, ‘Peter just wants to come on the show and talk about Doctor Who? That's great, but any idea why? Bit random, but brilliant. I love him, and I love Doctor Who, it's fantastic!’

“And then he came and sat there and kept saying all the time ‘When am I finished? When do you want me to leave?' Obviously he was just trying to work out when within the hour he should drop the bombshell.

“And then he just kind of casually let it into the conversation. I remember just trying to compute – 'did you just say what I think you just said? Are you actually leaving?’

“And his eyes were just brimming with tears, and it was obviously a hugely big deal for him. A very emotional experience to tell everyone that this was it, that this was his time to move on. And I felt really privileged that he decided to do it on the show.”

Capaldi's tribute to Doctor Who on Whiley's show was clearly heartfelt: "One of the greatest privileges of being Doctor Who is to see the world at its best," he told Whiley.

"From our brilliant crew and creative team working for the best broadcaster on the planet, to the viewers and fans whose endless creativity, generosity and inclusiveness points to a brighter future ahead. I can’t thank everyone enough. It’s been cosmic."

And as the big moment of his exit approached, you might have expected Capaldi to get all the more upset – but when Whiley caught up with him again on the final filming days of upcoming Christmas special Twice Upon a Time (when his Doctor will regenerate into Jodie Whittaker’s incarnation) she instead found him in a MUCH more chipper mood.

“I think he's past that now,” Whiley told us.

“I got the impression that dropping the bombshell and telling everyone that he's leaving was the difficult bit, the really really difficult bit. And actually acting it out, he was being the actor, and he wanted to do it to the very best of his abilities.

“I think it was kind of the relief of announcing he was moving on – and it was all about giving the viewers the best that he could, just making the best exit, and making that show just right for the viewers.”

Though of course, Whiley admitted she might not have seen Capaldi during his most emotional moments.

“Maybe at the very end of the day after we'd left, I'm sure when they finally went to say goodbye to each other it was emotional,” she suggested.

“But [when we were there] it was more about doing the job very well, doing Doctor Who justice.”

From what we’ve seen so far, it seems like they’re doing a pretty good job – and we’re well prepared for our very own crying fits this 25th December.

The Jo Whiley – Access All Areas Doctor Who Special airs on BBC Radio 2 from 8 to 10pm on Thursday 21st December