LONDON — David Cronenberg‘s London-set thriller “Eastern Promises” opened the Times BFI London Film Festival on Oct. 17 in Leicester Square revealing the Canuck helmer’s leftfield use of the capital.

“The reason you might not recognize London in this film is that it was shot in Prague,” Cronenberg joked.

Pic used unusual London locations, including the Finsbury Park Turkish bathhouse, where a naked Viggo Mortensen is brutally attacked by rival gangsters. Naomi Watts and Vincent Cassel were among those on hand to add star wattage to the black tie occasion. The screening and packed after-party at Cubitts Yard attracted a slew of directors including Stephen Frears, Michael Winterbottom, Stephen Woolley, Terry Gilliam and Alan Parker.

The following night, the fest’s premiere of “The Interview” brought out the pic’s star Sienna Miller and helmer Steve Buscemi.