Jenna Coleman is expected to leave the hit BBC series Doctor Who later this year. - BBC

It is thought the actress will make her last appearance as Clara Oswald before the Christmas special, which sees the return of Alex Kingston as River Song.

Coleman joined Doctor Who in 2012, and has starred alongside two Doctors, Matt Smith and Peter Capaldi.

The Mirror reports that her next role will be as Queen Victoria in a major ITV drama series.

The 29-year-old, who began her career in the soap opera Emmerdale, is expected to play the Queen from the age of 18 and in the early years of her reign.

However, ITV said it was not making "any announcements about casting presently".

The BBC has also declined to confirm Coleman's departure from Doctor Who.

In an interview published in the Radio Times this week, the actress said she had always known her time on the show was finite.

"You're in Doctor Who knowing it will never last," she said.

"It's constantly regenerating, so you want to make your time count and enjoy the adventure for the fleeting time you're here."

ITV announced in May they would be making an eight-part series about the life of Queen Victoria.

It is being made by the producers of Poldark and has been created and written by the novelist Daisy Goodwin.

Filming starts this month and it is understood that Coleman has already filmed her final scenes for Doctor Who, which returns to BBC One on Saturday.

Rumours of the star's departure circulated last year, after a cliffhanger in the series eight finale, Death In Heaven.

Fans had to wait until the end of the Christmas Day special to find out whether Coleman's character would return.

Chief writer Steven Moffat later confirmed the actress had initially asked to be written out of the drama.

"That was her last episode," he said. "Then she asked me if she could be in [the] Christmas [episode]. So I said, 'OK, I'll write you out in Christmas.'"

"She came to the read through and did the 'write out' version - and again changed her mind."

"But the truth is I never wanted her to go. And with Last Christmas, I'd already written the alternative version where she stayed, and I preferred that version.

"Frankly, I didn't want to lose her. She's an amazing actress, and she never stops working to make Clara better. I was very happy to go the extra mile to make sure we could keep her."

Capaldi, who plays the current incarnation of the Doctor, said he was "thrilled" Coleman had signed up for another series.

While the actress said it was "wonderful" to stay, adding she "couldn't walk away with the story being unresolved."