The Diary: Andrew Scott; Eric Cantona; Art on the Underground; Jessica Hynes; Martha Marcy May Marlene

Moriarty returns

Fans of Sherlock need not feel bereft: a new film, starring Andrew Scott, aka Moriarty, has been released online. Scott has teamed up with the playwright Simon Stephens and producer Andrew Porter (Stephens' uncle) on Sea Wall, a devastating 33-minute monologue by a young father. Scott first appeared in Stephens' play at the Bush Theatre in 2008, then at the Traverse a year later in a critically adored production. "I've had 21 plays produced and I'd never say any one was my favourite. But if I had to, I'd choose Sea Wall," says Stephens. "One of the things I love about theatre is its impermanence. But we both wanted to keep this one alive. We expected nobody to watch it." In fact, it has already been downloaded 1,800 times at www.seawallandrewscott.com. Stephens has a busy year ahead, with five new plays opening in 2012. The first is Three Kingdoms, a trilingual thriller at the Lyric Hammersmith in May and a play for teenagers in the model of the Belgian company Ontroerend Goed. And he's just put the finishing touches to adaptations of A Doll's House for the Young Vic and The Curious Incident of the Dog in the Night-time for the National. Stephens wrote the latter "as a favour" to its author Mark Haddon. "On the understanding that we might not get a commission and that I was allowed to fail. Then we took it to Marianne Elliott and Nick Hytner and they loved it. The key is replicating the directness of Christopher's voice. It would be crazy not to find a theatrical angle on that. I think we've managed it."

Cantona's own goal

Eric Cantona is a man of many parts: footballer, kung-fu fighter, campaigner, one day, perhaps, President. Oh, and actor. At the end of March he will appear as a gun-toting, car-chasing detective in the French thriller Switch. The film, a Bourne Identity meets The Fugitive-style caper, stars Karine Vanasse as a French Canadian who enters into a homeswap but wakes on her first morning in Paris to find a decapitated man in her new home – and then goes on the run. The film drew average reviews when it was released in France last year, with Cantona's performance largely praised as "credible". L'Express, though, was more damning: "Eric Cantona... n'est pas acteur. Dommage."

Film-makers go underground

Delays are par for the course on the Jubilee Line but at least the Olympic crowds at Canary Wharf station will have something to look at thanks to Art on the Underground's new year-long programme of screenings in the ticket hall. The screen will be curated by four film institutions including Animate Projects, LUX and the BFI, which will show archive films inspired by the seasons in December. First up, from Thursday, is Film and Video Umbrella, which will show work by artists including Marcus Coates' witty mix of barcode scanners with birdsong and Melanie Manchot's portrait of an East End street party. The longest film, Suki Chan's time-lapse sequences of London by night, lasts more than 21 minutes. Just the thing to pass the time until the next train to Stanmore.

Hynes' heist

Jessica Hynes, co-creator of Spaced, is returning to her writing roots, creating a new play for Bad Physics theatre company. Bank Heist was performed in the Old Vic Tunnels earlier this month. The eight-minute drama played out in the aftermath of a bank robbery, casting the audience as hostages. "The first three minutes were about terrorising them. We had some pretty convincing replica guns and plants in the stalls," says Dan Bird, director of Bad Physics. "We've always loved Jessica's crazy, comic writing and we expected her to come up with a bit of a caper. She wanted to write something very interactive. In the end it was incredibly intense."

Site-specific cinema

There's no escape: that's the message of the gloriously tense film Martha Marcy May Marlene starring Elizabeth Olsen as a disturbed girl who runs away from a cult. As if the movie wasn't enough of an ordeal, London's Curzon Soho cinema has transformed its bar into the creepy commune in the Catskills, immersing visitors in the film's world of mountain views, rough-and-ready wooden benches, and washing lines. The cinema held an exhibition of Art Deco ballet posters for Black Swan and made the bar into a messy teen bedroom for We Need to Talk about Kevin. Much more striking than the popcorn and cardboard cutouts that litter cinema lobbies.