The UK’s first festival of improvisation returns to the Bristol Old Vic next month. Set up as an experiment three years ago by Bristol Old Vic artistic director Tom Morris, Bristol Jam has since become a draw for some world-class acts, with impromptu performances taking place not just in the main auditorium but also in the paintshop, studio, cafe, walkways, the whole building.

Between November 5 and 11, there will be comedians, musicians, poets, performers, dancers, actors, singers and storytellers, but who knows what will happen once they arrive on the cobbles of King Street. The Old Vic promise that they will be “unleashing impromptu, audience-driven, world-class live performance”.

Artists in the theatre space include beatboxer Beardyman, last seen as one of the Brisfest headliners at Ashton Court, with visuals from Bristol’s very own Mr Hopkinson as he creates of a new album with the titles of each song suggested by the audience; Edinburgh sensation and Twenty Twelve actress Sara Pascoe; and a live music double-header from Polar Bear and Hauschka.

One of the most exciting elements of Bristol Jam this year is the 30-hour Improvathon, with 30 of the UK’s most talented improvisers “going the distance in one of the craziest undertakings of the theatrical year”.

Starting at 6pm on Friday, November 9 and running all the way through until midnight on Saturday, November 10, each episode lasts two hours, with audiences able to drop in for a single session, stay for more or brave the whole bonkers event with a 30-hour pass and copious cups of tea and coffee.

Throughout the week, Georgia Jacob will be curating live drawing, and Mr Hopkinson will be let loose late at night in the Paintshop, which will be the venue for the festival’s late bar.

For the full lineup, visit www.bristololdvic.org.uk/bristoljam.html.