By Matt Smith, Entertainment Correspondent in Cannes

It was probably the most popular press conference so far.  The sight of Angelina Jolie and Brad Pitt together in Cannes, enough to leave standing room only inside and a scrum outside the press room.   

In fact, as I write this, I can hear the photographers still screaming outside as they try for a shot of of the couple leaving the main building here.

They're here to launch their new joint film project A Mighty Heart.  She stars in it, he produces it.  The film, directed by Brit, Michael Winterbottom (24 Hour Party People, 9 Songs), tells the story of murdered American journalist Daniel Pearl. 

Pearl, as the south Asia bureau chief for the Wall Street Journal, was researching a story on shoe bomber Richard Reid in Pakistan, when he decided to go and meet a contact.  He was kidnapped and later murdered by a militant group who claimed Pearl was a CIA agent.  He'd been beheaded.

His wife Mariane (played in the film by Jolie), was six months pregnant when it happened.  She wrote a book about the ordeal - the basis for this new film.  She was also here in Cannes to help promote it.  Here's the trailer:

Having watched it this morning, it's hard hitting and Jolie is extremely good as - and looks very similar to - Mariane Pearl.  Dan Futterman is a convincing Daniel Pearl, and the rest of the cast are also very believable.  It has real impact without resorting to melodrama and is by far the best film I've seen so far here at Cannes.

And given the serious nature of the story, it was also a pleasant change that most of the questions in the press conference weren't about relationships and babies, but about the film itself.  Even a reporter from the British tabloids asked a decent one.

Which meant we got good answers.  Angelina Jolie telling reporters that Mariane Pearl had seen the film and told her that she was very happy with how the story had been told:

Jolie said: "Right before the first day's shooting, I was very very nervous and didn't know if I really could do it at all.  And so for her to tell me that it was done right, I can't tell you how much that means to me."

Brad Pitt also handled himself well in front of reporters, admitting he sometimes prefers producing to being on camera.  He himself will be centre stage again later this week, when he launches Oceans 13.