Holmes and Watson
Holmes and Watson in the popular BBC seriesSherlock official

Filming for the fourth season of the popular British show Sherlock has been postponed.

Martin Freeman, who plays John Watson in the global hit series, has revealed that plans to start filming soon have been scrapped.

"It's very hard to get together," he told Digital Spy. "But it's one of those things where you have to at some point just go, 'We're going to do it now' - otherwise we could be having this conversation in three years."

He added: "There comes a point where you've got to p*** or get off the pot."

A BBC spokesman recently told Mirror Online that filming depends mainly on cast availability: "Conversations are still ongoing regarding Sherlock's return. Steven Moffat has already said that he has mapped out a fourth series, but it is always depending on cast availability.

"The last series was a fantastic hit for us and we're massively proud of the show," the spokesperson added, stating that every member of the team of is keen to start filming as soon as schedules work out.

During an online Q&A with fans after the series 3 finale earlier this year, Moffat and Mark Gatiss admitted it all comes down to the schedules of Benedict Cumberbatch and Freeman.

"Everyone is very keen to do more, but we have accidentally cast the two most successful actors in the world and schedules are tight," said the pair.