The BBC has pleaded with Doctor Who fans who’ve seen this week’s series finale not to post spoilers online. Showrunner Stephen Moffat also promised to release exclusive content if they don’t spill the beans.

The plea came after a blunder in the United States where a distribution error meant DVDs of the second half of the current series have gone out early — complete with the final episode that won’t be broadcast until Saturday. The discs weren’t meant to be out for another three weeks.

BBC Worldwide, which handles distribution, is currently looking into how the mistake happened. It said “We are asking fans who may have the discs not to divulge plot details so that fellow fans who have yet to see the episodes do not have their viewing pleasure ruined.”

The episode is set to involve a revelation involving the Doctor, most likely relating to his real name in some fashion.

The statement added that Moffat was willing to offer a trade: if fans keep things under wraps, he’ll post an exclusive clip of the current Doctor and his predecessors (Matt Smith and David Tennant respectively), which is almost certainly from the filming of a 50th anniversary special to air in November.

It seems highly unlikely the leak is some form of publicity stunt. Moffat has previously been passionately critical of people who discover plot points and reveal them before transmission.

On the face of it, this seems to be a losing battle: it appears video of Saturday’s episode is already doing the rounds of filesharing services.

However, even if details do leak online, it won’t necessarily affect the viewing audience. Last summer virtually the entire contents of the Olympics opening ceremony (including James Bond and the Queen) were published on a US website, four days in advance, but remained a secret to most of the British public — despite thousands of people being involved in the rehearsals.

(Readers: hopefully this should be obvious, but please don’t post Doctor Who spoilers in the comments section!)