MENTAL, a movie directed by Muriel's Wedding director PJ Hogan and filmed in Murwillumbah, will have its official opening night at Sunday's Australian International Movie Conference held at Jupiter's Casino on the Gold Coast.

The movie reunites Mr Hogan with actor Toni Collette who played the part of Muriel in Muriel's Wedding 17 years ago and plays the leading role in Mr Hogan's latest offering.

Mental tells the story of Shirley Moochmore, played by Rebecca Gibney, who suffers a breakdown and is committed to a mental hospital by her womanising politician husband, Barry, played by Anthony LaPaglia.

Barry is forced to take care of the couple's five teenage daughters while his wife is being cared for and to give him a helping hand, Barry takes on hitchhiker Shaz, played by Toni Collette, as a nanny.

PJ Hogan said "like Muriel's Wedding, Mental is based on a true story.

"When I was 12 years old my mother had a nervous breakdown and was institutionalised.

"My dad, not exactly Father of the Year anyway, found himself stuck with five kids he barely knew and couldn't talk to.

"But to be fair, we were a bunch of ratbags."

Lead actor, Toni Collette, said "the movie definitely has a really similar tone to Muriel's Wedding so that's something that I immediately loved and the story is fantastic.

"I think my character Shaz is completely outrageous.

"I get to say some of the best lines ever."