Benedict Cumberbatch and Martin Freeman outside 221b Baker Street BBC

Martin Freeman has admitted that he has no idea when Sherlock will return for a fourth series.

The actor, who plays Dr John Watson opposite Benedict Cumberbatch as Sherlock Holmes, said he was being kept in the dark regarding any plans.

Series 3 of BBC One's detective drama concluded on Sunday night, drawing in nearly nine million viewers.

It had been rumoured earlier this week that the Beeb want to fast-track the next series for a return on Christmas Day 2014.

"That's news to me," said Freeman in an interview with Access Hollywood. "People have told me that today. If journalists are saying it, it must be true. I don't know."

Freeman went on to say "I've not read any new scripts. So all I know is we all like the show, we all want to keep doing it for as long as we want to do it and as long as we enjoy it."

Sherlock series 3 premieres in the US this Sunday (19 January).