Cumberbatch admitted that the idea of how Moriarty is resurrected is “very good” but explained that he tries to put it out of his mind.
He added that both himself and co-star Martin Freeman, who plays Dr John Watson, like to approach a script with fresh eyes to maintain the surprise.
“… we get a rough idea of where it’s going to go before we get the script. But I like casually forgetting, not least because there’s a lot of other traffic between then and now but also because it’s more fun because it’s slightly more fresh,” he added.
Best moments from Sherlock
Best moments from Sherlock
1/9 Best Sherlock moments
Sherlock's 'dies' after he falls off the edge of St Bart's hospital. The nation mourned for all of five minutes before it was revealed that the super sleuth had faked his death
2/9 Best Sherlock moments
Sherlock and Moriarty go in for a kiss - prompting shipping theories to crop up across the internet.
3/9 Best Sherlock moments
Sherlock accidentally disrobes in Buckingham Palace in 'Scandal of Belgravia'.
4/9 Best Sherlock moments
Sherlock and Watson play a drinking game during Watson's two-man stag do. The rest of the evening ends in typcically raucous style.
5/9 Best Sherlock moments
Sherlock and Watson have a punch up in 'The Empty Hearse'. In possible the best fight since 'Bridget Jones's Diary', the pair tussled furiously when Sherlock surprised Watson by coming back from the dead.
6/9 Best Sherlock moments
Molly and Sherlock's Christmas present was one of the sweetest moments between the pair. The romance that viewers want to happen.
7/9 Best Sherlock moments
Sherlock exposes Sun journalist Kitty Riley, who pretends to be a big Sherlock fan.
8/9 Best Sherlock moments
The series one finale of 'Sherlock' left fans on tenterhooks after Moriarty strapped a bomb to Watson in a standoff with the detective
9/9 Best Sherlock moments
It was a partnership made in heaven - Sherlock and Watson meet for the first time.
At the end of the last series Sherlock was brought out of exile after Moriarty appeared to have returned from the dead. A gif repeating “did you miss me?” was broadcast simultaneously across the nation, even ending up on the lights at Piccadilly Circus.
Viewers saw Moriarty shoot himself in the head during a standoff with Sherlock on the top of St Bart’s hospital in London at the end series 2’s heart-stopping finale, where the famous detective also “died”.
Cumberbatch is currently at San Diego Comic Con to promote the animated film Penguins of Madagascar, unfortunately fans were not allowed to ask questions about Sherlock during the panel session.
He is also at the convention for The Hobbit: The Battle of the Five Armies, which will be released in December this year. Today the star posted a tongue-in-cheek selfie at Comic-Con with an excited (or terrified expression) on his face.
Sherlock will be returning with a special followed up by a three-episode series, filming is scheduled to begin in January 2015 with work on the fourth series taking place later next year.