Post your question for Life in a Day director Kevin Macdonald

Life in a Day, Kevin Macdonald's revolutionary crowdsourced film, premiered at Sundance earlier this year . Culled from 80,000 hours of footage submitted via YouTube and all shot on 24 July 2010, it's a gripping, moving document of human life and testimony to a remarkably ambitious act of curation. Last week in G2 , Macdonald – whose previous films include The Eagle, State of Play, The Last King of Scotland, Touching the Void and the Oscar-winning One Day in September, and who is currently in pre-production on a Bob Marley biopic – explains how he did it. On Wednesday lunchtime he'll be in the Guardian office for a chat with you, live on the film blog. So post your questions below, or email them in . Stuck for inspiration? Check out the questions posed to Macdonald by some of the 11 to 18-year-old members of education charity Filmclub in a webchat last Thursday .