BBC's "Sherlock" season 3 is currently airing in the U.S. The lissom, quirky detective had returned after a break of 2 years, on Jan 1, 2014, in the UK. The three episodes of "Sherlock" Season 3 did not manage to please everyone. However, there is no doubt that everyone is looking forward to season 4.

BBC has yet to officially announce seasons 4 and 5 of "Sherlock." However, Benedict Cumberbatch, Martin Freeman, Steven Moffat and Mark Gatiss have confirmed that two more seasons of "Sherlock" are in the offing. "It will continue until Benedict gets too famous," Moffat told The Hollywood Reporter.

"Sherlock" writing duo, Moffat and Gatiss, have indicated that they have already "mapped out" season 4. Also, they revealed, as reported by Radio Times, that they have come up with some of the best ideas for seasons 4 and 5.

"Rather excitingly, Mark and I, for no particular reason, we just got out of the rain and sat at the top of the [Sherlock] production bus... and we just started plotting out what we could do in the future," said Moffat, as quoted by Radio Times. Moffat also revealed that they have plotted out the entire seasons 4 and 5, saying, "The ideas we had that day, I thought were the best we've ever had."

Meanwhile, although a good percentage of "Sherlock" fans did not welcome the introduction of Mary, as Dr Watson's love interest and wife, she's here to stay. She is going to be an integral part of the upcoming seasons. "Mary's absolutely here. We don't just off her," Moffat said to The Hollywood Reporter.

There are chances that Irene Adler will return in season 4, too. She is "The Woman" who refuses to go away from Sherlock's mind. The writing duo, however, refused to confirm. Moffat said that if they come up with a good idea, it can be possible.

Cumberbatch said to The Hollywood Reporter that he intends to keep doing "Sherlock" as long as his schedule permits. He finds playing the role of Sherlock "very invigorating."