As series eight of Doctor Who draws ever closer – it launches on 23 August – a ‘secret’ promo trailer has been released by the BBC.

The 30-second video is for the show’s first episode ‘Deep Breath’.

Scroll down to see video

It starts with a roaring dinosaur and shows a redecorated Tardis and Peter Capaldi attired in just his jammies.

The aptly-named episode sent the hearts of thousands of Doctor Who fans aflutter, after the broadcaster appeared to have released it on the sly on Twitter yesterday without notifying anyone.

This sort of guerrilla marketing works a treat, however, and word soon spread.

The clip, which shows the Doctor landing in Victorian London, has since been uploaded to the BBC’s website.

Leicester Square will be the location of the premiere of the new Doctor Who series, with Capaldi, Jenna Coleman (who plays his companion Clara), and Steven Moffat all taking part in a special Q&A session on the day that households around the UK will also see the first instalment.

The session will be hosted by Zoe Ball.