Anna Passey explains Sienna's mysterious absence from Hollyoaks

Her pregnant sibling is the couple's surrogate, but doesn't realise Sienna knows Lib and Brody had to conceive the old-fashioned way when Ms Blake's last embryo wasn't viable. Cue an awkward reunion…

"Sienna is heartbroken to see Brody forming a romantic relationship with her sister," reveals Anna Passey, who plays the returning fan favourite. "She had good reason to leave, to get the children away from Warren, then when Brody helped him try and track her down she felt betrayed. But she is sad to see her boyfriend moving on.

"The baby was meant to be hers and Brody's and they were going to raise it together. Now they're not in a relationship and with her knowing the baby is actually Liberty's biologically, I'm not sure what she will do next."

'Brienna' fans need not worry too much as Passey hints the couple's connection is too strong, and too popular, to write off just yet.

"Sorry Lib, but I think Brody and Sienna are made for each other!" she laughs. "Brody is hurt and confused by his sense of responsibility for the baby, but his heart truly belongs to Sienna. They have both been through an awful lot and have a mutual understanding. There is such love and compassion, and it's great the audience love them as a couple."

There are more pressing things on Sienna's mind, as her son Sebastian is still seriously ill. "She has been on the run in Wales with her twins, but the care he needs is back with the specialist doctor in Dee Valley hospital, so Sienna has decided to come home to get the treatment.

"Sienna also thinks Warren will be chasing after her and is not expecting him to be in the village. When she finds out he is still there she will have to fight her instincts to run again.

"She despises Warren, understandably after their history when he took the twins from her. But Brody has a way of drawing the best out of people, and helps Sienna change her opinion on the situation and see Warren has good intentions."

Could we see a thawing between the warring parents for the sake of sickly Sebastian? "It would be an unusual co-parenting set-up, but the health of their children is the most important thing to both of them. If they can see that, hopefully they can work together."

Sienna fled in mid-January and her last, very brief, appearance on-screen was in February - her extended break was to accommodate an exotic holiday for Passey and boyfriend Kyle Pryor, who formerly played Hollyoaks' bad boy Laurie Shelby.

"I've been off having an epic adventure in New Zealand," she shares. "It was my first time visiting so I had an awful lot to see, and a tonne of fun outdoor pursuits to try. Turns out I'm obsessed with kayaking! We spent weeks living in a camper van, which was one of the best life experiences I've ever had."

Visit our dedicated Hollyoaks page for all the latest news, interviews and spoilers. If you’re looking for more to watch check out our TV guide.