Doctor Who's Millie Gibson addresses how much we'll see of Ruby in season 15

It's still unclear though how large a role Gibson will play in forthcoming episodes, with TVLine reporting that she will appear in just two instalments – episode 4 Lucky Day and episode 8 The Reality War.

RadioTimes.com had the opportunity to quiz Gibson herself about this at the launch of the new season and while she wouldn't confirm an episode count, the star did insist she appears "a lot".

"I don't know how much I can say, but a lot... enough to feel the love from [Ruby], as always!" she laughed.

Promotional images and trailer footage have also revealed that Ruby will again be sharing scenes with Kate Stewart (Jemma Redgrave) and the UNIT team. "She definitely has scenes with UNIT – I have scenes with the beautiful Jemma Redgrave, and it was so much fun," Gibson confirmed.

"UNIT are such a... I mean, the clue's in the name, they're a unit, such a strong team to be a part of, so I really enjoyed Ruby's dynamic amongst the crew... and The Vlinx! So yeah, she's got a bit to do with them."

Lucky Day will explore Ruby's life back on Earth after she was reunited with her long-lost mother in last year's finale Empire of Death and will see Gibson's character suffer from PTSD as a result of her dramatic adventures in time and space.

"In episode 4, there's a brilliant storyline of how Ruby’s getting on with her family, and it kind of goes on to the journey of her waiting for the Doctor and still feeling a bit lost," she explained.

"It’s such a cool concept to go back to a companion and see how they’re getting on after that wild ride."

We will, of course, eventually see her back alongside the Doctor. "It was pretty heartbreaking," Gibson said of the pair's previous parting of the ways. "So as you can imagine, it's a pretty cool reunion!"

The Little Mermaid star Jonah Hauer-King will appear in Lucky Day as Ruby's new love interest Conrad Clark.

Other guest stars set to appear in the new season include Freddie Fox, Christopher Chung, Rose Ayling-Ellis, and a returning Anita Dobson as the enigmatic Mrs Flood.

The season will feature eight episodes, written by Russell T Davies alongside contributors Pete McTighe, Juno Dawson, Inua Ellams and Sharma Angel-Walfall.

Davies has reiterated that he is still waiting on an answer as to the show's future after the next season – and that he "hope[s] it comes back".

"There's no decision until after season 2," he affirmed. "It's funny, because even people who work on the show think that means we're having secret meetings about it. People I work with every year say, 'What's really happening?' and I'm going, 'Nothing! No meetings, nothing.'"

Disney Plus has co-produced the last two seasons of the show alongside the BBC, so needs to sign off on more episodes before production can begin.

Doctor Who will air from Saturday 12th April at 6:50pm on BBC One, with new episodes available from 8am on Saturdays on BBC iPlayer in the UK. The series will be available on Disney Plus outside of the UK.

Read more:

• Doctor Who season 15 episode might not air on BBC One – Russell T Davies explains why
• Doctor Who unveils new episode 1 images – what has Mrs Flood seen?
• Doctor Who star joins cast of Fantastic Four: First Steps

Check out more of our Sci-Fi coverage or visit our TV Guide and Streaming Guide to find out what's on. For more from the biggest stars in TV, listen to The Radio Times Podcast.