Sherlock stars Benedict Cumberbatch and Martin Freeman could still be playing the successful sleuths in 20 years if the show's co-creator Mark Gatiss gets his way.
Mark created the hit BBC show, a modern re-imagining of Arthur Conan Doyle's classic detective stories, with Doctor Who supremo Steven Moffat.
Filming of the third series starts in March and Mark said he hoped the pair could equal Basil Rathbone and Nigel Bruce, who made a string of films as Holmes and Watson and were still playing the parts into their 50s.
He said: "I think one of the wonderful things, if everybody is up for it, is starting as we did with Sherlock and John as much younger men than they're usually portrayed as, we can play with the idea of them growing up.
"I'd love the idea of Benedict and Martin the same age as Basil Rathbone and Nigel Bruce. Who knows? Why not?"
Sherlock has won millions of viewers and been a critical hit, picking up awards including a Bafta for Best Drama.
It was named the top television show of 2012 in a Radio Times poll and an episode featuring Lara Pulver as dominatrix Irene Adler was the most popular show on the iPlayer at one stage - having been watched around 2.5 million times.