The Point stars Caerphilly-born TV presenter and actor Matt Johnson, who plays the younger brother of a man who is convinced he does not want to live anymore.
The film will be shot in the Brecon Beacons, near the home of its scriptwriter Jasper Warry.
Mr Johnson is an active ambassador for the mental health charity Mind.
He recently presented the documentary Iselder a Fi (Depression and Me) discussing his own personal experiences with depression for S4C.
As well as appearing in The Point, he will also be the executive producer.
He said the script was "one of the best he's ever read".
"It wonderfully tackles the hugely important issues of mental health in a distinct, moving and humorous way."
Mr Warry said he was "made up" with Mr Johnson's involvement and hopes to start shooting in November.
He said they will be using local talent wherever possible, both in front and behind of the camera.
A Welsh feature film which tackles mental health issues is due to be shot in Powys later this year.