US actor Martin Sheen has bowed out of an on-stage appearance and interview at this month's Regus London Film Festival, the event has confirmed.

The UK festival said that Sheen's decision to pull out was due to "work commitments", although it comes only days after Bruce Willis said he would stay home because of family concerns. Sheen was to have attended in support of Apocalypse Now Redux.

Italian director Nanni Moretti, whose Palme d'Or winning The Son's Room plays at the festival, will step into the breech by giving a replacement public interview.