The hit BBC drama will return for a Christmas special next year, with a three-part series to follow in 2016, reported Digital Spy.
"I can't give any plot away... But their pitch for the Christmas special and the series beyond that is just phenomenal," Cumberbatch said.
"We've never seen ('Sherlock') being really pressed yet, so that will be interesting."
The 38-year-old Emmy winner also confirmed that he is keen to make more 'Sherlock' beyond the next four episodes.
"I'd like us to finish on a high, but we'll do it until we don't want to do it anymore," he said.
Steven Moffat previously promised that he and 'Sherlock' co-creator Mark Gatiss have a "devastating" plan in place for the new series.
