Doctor Who is celebrating its 50th birthday – and you’re invited to the party.

A special feature-length episode of the sci-fi series is being screened in 3D at cinemas around the county, at the same time as it is broadcast on BBC1.

Titled The Day of the Doctor, it will feature current Doctor Matt Smith, along with many other familiar faces from the long-running series, including previous Doctor David Tennant and former assistant Billie Piper.

The action-packed adventure sees something terrible awakening in London’s National Gallery in the present day; a murderous plot afoot in Elizabethan England; and an ancient battle somewhere in space.

During the past five decades, 11 actors have played the Doctor, and this episode will be one of Matt Smith’s last.

The Doctor’s 12th incarnation will be Scottish actor Peter Capaldi, famous for his role as acerbic spin doctor Malcolm Tucker in BBC comedy The Thick Of It.

But departing Doctor, Matt Smith denied there was any rivalry between the old and new Time Lords.

“We’re not competitive. There’s a funny bit in the script between the 10th and 11th Doctors comparing Sonic Screwdrivers, so there’s competitiveness in the story, but not off-screen. We just had a laugh.”

He added: “It’s a thrill to be in the 50th anniversary episode. I feel very proud to be part of Doctor Who, and it’s a credit to everyone who started the show back in the 1960s that it’s come this far.”

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The Day of the Doctor will be shown on BBC1 and at participating cinemas at 7.50pm on Saturday, November 23:

Ashford: Cineworld
Broadstairs: Westwood Cross Vue
Canterbury: Gulbenkian
Chatham: Odeon
Dartford: Showcase Bluewater
Maidstone: Odeon
Rochester: Cineworld
Tunbridge Wells: Odeon