Actresses Keira Knightley and Eva Mendes sidestepped the red carpet at the Rome Film Festival opening after protesters picketed the event.
As actors, directors and screenwriters demonstrated against the Italian government's cuts to arts funding, the stars used a side entrance to enter Rome's Auditorium Parco Della Musica.
The showing of their latest movie, Last Night, began almost two hours late.
The festival is scheduled to run until 5 November.
Last Night director Massy Tadjedin told demonstrators she was sympathetic to their demands.
"We are pleased to renounce the red carpet and support you," she was quoted as saying by the ANSA news agency.
In the movie, Knightley plays a woman who becomes jealous when she meets her husband's new colleague, played by Mendes.
After bumping into a former boyfriend, she finds herself faced with the same dilemmas about cheating as her husband.
"I think everyone can recognise the scenarios that happen within this piece," said Knightley ahead of the premiere.
"I think that most people have at least been one person, if not all four, at some point in their life.
"In most films there are goodies and baddies. What I liked about this script is that it did not take a standpoint, that there is no conclusion."
The movie also stars Sam Worthington from Avatar and French actor Guillaume Canet.
Other events to take place during the festival include a screening of a digitally remastered version of La Dolce Vita, to be attended by US director Martin Scorsese.
Jim Loach, son of British director Ken, is also set to unveil his film debut, Oranges and Sunshine.