14. Lots Of Family Members Guest Star
You often hear the cast and crew of a long-running TV show say they're like a family, but in the case of Sherlock that's literally true. Thanks to the big publicity push around the third series everyone should know that Amanda Abbington, who plays Mary, is Martin Freeman's real life partner, but there's a lot more family members littered about. Sherlock's parents are actually Benedict Cumberbatch's, young Sherlock is played by Steven Moffat's son, the lawyer from The Reichenbach Fall is Mark Gatiss' husband and the Holmes' dog in reality belongs to the Freemans. It spills over behind-the-scenes too; Steven Moffat created the show, his wife produces it and his mother-in-law writes. Don't be surprised if Benedict Cumberbatch's new fiancée, Sophie Hunter, pops up in Series 4.