Rufus and Martha Wainwright concert added, as is film about the Prince of Wales.

The first Sundance London event has announced three panels, including an afternoon with composer Harry Gregson-Williams [pictured], a documentary flash lab including Lauren Greenfield, Eugene Jarecki, Jeff Orlowski and Jess Search; and a UK vs US indie filmmaking panel featuring Josh Radnor, So Young Kim, Ry Russo-Young, James Marsh and Gurinder Chadha.

The other special events planned include Rufus and Martha Wainwright performing and participating in a Q&A after the world premiere of Lian Lunson’s film Sing Me The Songs That Say I Love You ~ A Concert for Kate McGarrigle.

Placebo, which is playing a previously announced concert at Sundance London, will also be participating in a Q&A after the screening of Charlie Targett-Adams’ documentary about the band, Coming Up For Air.

Also, Robert Redford will introduce Harmony, a film about the environmental work of The Prince of Wales, and there will be a 25th anniversary screening of River’s Edge.

The event runs April 26-29 at London’s O2.