Alex Kingston and Paul McGann speak about crossing the time-streams.

“Alex? Hello, I’m Paul.”

This is it. The first encounter between arch archaeologist / charismatic con-woman River Song and her future husband, the eighth incarnation of the Time Lord known as the Doctor.
Alright, so it’s really their Earthly alter-egos – Alex Kingston and Paul McGann – meeting for the first time. But it remains quite a moment and Digital Spy is there to witness it, spending a day at the studios of Big Finish – producers of original Doctor Who audio-plays for the past 17 years.

“I think people out there maybe assume that all us Doctor Who types know each other,” McGann says. “But of course ordinarily you wouldn’t meet, so I felt very excited at the prospect of working with Alex.”I’ve just got back from a fan show in the States and there were fans there going quietly nuts about the prospect of the River Song Diaries, and the idea that we’re gonna meet. There’s lots of excitement out there, and quite right too.”

River and ‘Eight’ will cross paths, after a fashion, in The Diary of River Song: Series One – a new box-set that will spin Kingston’s character off into new adventures, and the latest release in a massive catalogue produced by Big Finish since 1999.

“One of the fans asked me if I would ever consider doing these – and to be perfectly honest, I didn’t even know they existed,” Kingston admits. Although her co-star insists that awareness of what Big Finish do is ever on the rise, even amongst Doctor Who fans.

“Particularly in the last three or four years – since the 50th anniversary in fact – I’ve been noticing a real spike in interest, particularly from the American fans,” says McGann. “They’ve finally twigged about the audios.

“I don’t think they’d quite realised, for one reason or another, but now they have – and according to the business model that Big Finish has, the more they buy, the more we can make.

“So we’re making more and we’re getting better at them – the stories are getting better all the time and it feels like good times.”

The ‘stories’ take the form of full-cast audio plays – like the sort you might hear on BBC Radio 4, but available as a CD or download. And even after all these years, Big Finish’s output – and the way in which it interacts with the Doctor Who television series – is still evolving.

When McGann reprised his role as the Eighth Doctor on-screen for a special anniversary minisode – 2013’s ‘Night of the Doctor’ – Who show runner Steven Moffat snuck in references to companion characters that up til that point had only featured in the audio-plays.

Doctor Who fans, and particularly Big Finish addicts, went nuts. In a good way.

“It was a gracious thing on Moffat’s part,” McGann says. “I’m not saying it cemented anything formally – it didn’t have to – but it’s a clue to how close Big Finish are with Cardiff, and how close they work together – swapping intelligence and people and stories.

“For the fans, it was great because it sort of canonised things. That appeals to them, that side of things, so it was a good move all round. It felt neat, and right.”

That relationship became even more sympatico in 2014, when Big Finish’s licence was expanded to include plays based on Doctor Who post-2005, and not just the classic era.

Last year saw new audio adventures for Osgood (Ingrid Oliver) and Kate Stewart (Jemma Redgrave) as part of UNIT, as well as John Hurt’s haunted War Doctor. While David Tennant will be back as the popular Tenth Doctor in May 2016.

The return of River – no time at all after her most recent TV appearance – is another big accomplishment, says McGann.

“This is gold-plated,” he enthuses. “You can’t get better than this… and again, it’s part of the strength of the union. A kind of endorsement of Big Finish and the audio adventures.”

“It’s been really fun – the episodes have been extremely well-written,” Kingston adds. “When we’ve completed each episode, I’ve thought, ‘wow: I want to film this episode now’. Because they’re so visual.”

Of course, River running into the Doctor at this stage in his lives poses something of a timey-wimey quandary – since, from his perspective, they don’t meet til he’s David Tennant.

“She has to be quite careful because he doesn’t know who she is,” Kingston confirms. “She can’t disrupt or spoil their history so the playfulness that one has seen with River and her other Doctors. It can’t go to that degree.

“But definitely there’s some fruitiness with some of the other characters that comes out,” she adds, with a grin.

Kingston says she “never imagined” River would become such a popular character – much less that the character would land her own spin-off series.
“It’s been fabulous – just being able to explore the character – and I would imagine it’s probably been fantastic for Steven Moffat as well,” she says.

“Funnily enough, in the actual filmed series, Steven was the only one that wrote for River. He didn’t really allow any of the other writers to write for her. And so actually this is the first time that anybody else has been able to put words into River’s mouth.”

Whether or not Moffat writes for River again – her appearance in Doctor Who’s 2015 festive special ‘The Husbands of River Song’ seemed to bring the character full-circle – Kingston is more than keen to continue working with the Big Finish team.

In fact, she wants to keep plotting new adventures for River and playing the character potentially well into old-age…

“I’ll be wheeled in… or I’ll stumble in with my Zimmer frame!” she laughs. “I mean, I have to say, my goodness, I heard Tom Baker on the radio yesterday and he was doing an advert for something…

“I don’t know how old he is now, but his voice was so present and energised and clear and my goodness, he’s still so good at it. So I hope that I have that longevity as well – it’d be fantastic!”

The Diary of River Song: Series One is out now and available to buy from bigfinish.com.