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Doctor Who has a feisty new sidekick, and you get the feeling she has a little bit of a crush on the time lord.
There's always been chemistry between the doctor and his female companions but when medical student Martha Jones meets him there's more allure than usual - in Martha's mind at least.
"There is this sort of push and pull of power quite early on," says actress Freema Agyeman who plays Martha in the news series, which starts this weekend.
"But the thing with their relationship is it keeps evolving. It starts off him being teacher and her being student, then it shifts and she becomes carer for him, and then it's best friends, and then, in her heart, he's a potential love interest," she laughs.
Martha replaces Rose Tyler (played by former teen pop star-turned actress Billie Piper) who was the Doctor's companion when the show made its comeback on New Zealand screens last year.
Apart from a television movie in 1996 Doctor Who had not been made since 1989 when its popularity waned. However, with actor Christopher Eccleston as the ninth doctor the new series sparked a Doctor Who revival.
David Tennant is the show's 10th doctor and his oddball awkwardness and dark, yet laid-back, sensibility recalls the time lord portrayed by Tom Baker throughout the 70s.
Agyeman is a Tennant fan. "The part just requires so much energy and, I don't know what it is, this kind of bounce he's got to the character as well as this quirky darkness," she says.
"It's a very complex character and he just manages to switch on this light and burns really bright with the part and then he goes back to speaking in his Scottish accent and becomes something quite different."
He needs to burn bright if he's going to keep up with Martha, a clever, inquisitive and strong-minded medical student who is a stark contrast to the younger and more impressionable Rose.
"Martha chooses to go with the Doctor for different reasons than Rose who was going because she seemed to be disgruntled with her life and he helped her discover herself.
"Martha seems to have all her plans laid out and she goes with him because she can't pass up the opportunity to learn more. But as she goes and does that she wants to ask why and how - and she's a much more challenging companion for him.
"And she's training to be a doctor so she thinks she's capable of reacting in certain situations - so where the Doctor would react she would react just as quickly."
At times the Doctor finds himself struggling to respond to Martha's questions and "there's a couple of times where he just can't be bothered to explain".
Getting the part of Martha is a dream role for 28-year-old Agyeman, who has appeared in British soap Crossroads, popular shows like The Bill and Casualty and had a role in last year's Doctor Who as Adeola Oshodi who was killed by the Cybermen in the episode Army of Ghosts.
"It was beyond my dreams getting a role like this," says the London-born actress who is half Iranian and half Ghanaian.
"When I got the call to say I'd got the job I was bombarded with all these thoughts and emotions because up until then I hadn't allowed myself to entertain the idea of getting it.
"When I got it, though, it was huge because this is one of the most sought-after female roles because it's just such a quality show - quality writing, quality effects, and it's just really slick."
She's a sci-fi fan and grew up watching everything from Star Wars, Star Trek and The X Files, and more recently Charmed and SG-1. She watched Doctor Who in the late 80s when Sylvester McCoy was in the role.
"A lot of people have said that by then it had lost its way a little bit but I enjoyed it as a child at the time.
"But yeah, apparently it kind of lost its way and so it took someone with real vision and genius to bring it back."
That person was writer and producer Russell T. Davis who wrote top British drama Queer As Folk and spearheaded the Doctor Who revival by simply staying true to the show's core traditions and then modernising them.
Agyeman says while Doctor Who is science fiction, there is still a certain believability about the show and she thinks there are three main reasons it is successful.
"First, the imagination that it has, that you can travel to all these amazing places and do all these amazing things. But also, on a very basic level, it's about emotions that other people can connect to.
"And even the special effects stuff, it's not ridiculous and it kind of takes you along with it and doesn't slap you out by its ridiculousness."
Once again in this series the Doctor comes face-to-face with his evil enemies the Daleks.
He also runs into ruthless plasmavore Judoon, and the particularly nasty Family of Blood headed by the very creepy Baines.
"For me it's not necessarily the shrieking, shouting and fast-running monsters that are the scariest, it's the quiet still ones that are more creepy," Agyeman laughs.
In the new series she also gets to meet William Shakespeare - a personal highlight.
"You know what?" she says sounding chuffed. "I did English A-levels and I absolutely adore studying Shakespeare, so when people ask me what time I would like to go back to, I love that Elizabethan, Jacobean period. I just adore it.
"When I found out that on episode two we were going to go back to 1599 to meet William Shakespeare I was beside myself.
"And then I was told he takes a bit of a shine to me and I thought, `That's me'."
As she says, it's her dream role.
LOWDOWN
What: Doctor Who
Who: Actress Freema Agyeman as Martha Jones, the Doctor's new companion
When: Sunday, 7.30pm, on Prime
Trivia: David Tennant is the show's 10th Doctor Who
