Samuel L. Jackson and Pierce Brosnan cast in Unholy Trinity

Samuel L. Jackson, Pierce Brosnan and Brandon Lessard are starring in 'Unholy Trinity'.

The trio have boarded Richard Gray's Western which is currently shooting in Montana after securing a SAG-AFTRA Interim Agreement that enables work on the project to continue despite the ongoing actors' strike.

The movie is described as a tale of revenge, dark secrets and buried treasures. It picks up in the moments before the execution of Isaac Broadway as he instructs his estranged son Henry (Lessard) to murder the man who framed him for a crime he did not commit.

Determined to fulfil his father's wish, Henry travels to the town of Trinity but an unexpected turn of events leaves him trapped in the area and caught between Sheriff Gabriel Dove (Brosnan) and the enigmatic figure of St. Christopher (Jackson).

Lee Zachariah is the writer behind the movie that is being executive produced by Amadeus Productions.

Gray told Deadline: "Thrilled doesn't even begin to describe how we feel about collaborating with such exceptional talent on 'Unholy Trinity'.

"It's a captivating story, and we feel fortunate to be able to make an epic Western during the strike, working alongside SAG every step of the way. Paradise Valley, Montana, is a spectacular location and the ideal backdrop for this special story."

Meanwhile, Samuel is also set to star as the US president in 'The Beast'.

The movie's title refers to the presidential limousine that is nicknamed 'The Beast' by the Secret Service. The impenetrable vehicle is stocked with grenades, shotguns, armour plating and bombproofing.

When a hostile militia coordinates a coup against the United States, the president (Jackson) discovers the extent of The Beast's highly classified capabilities.

Separated from his wife, the president must control The Beast – and the monster that lurks inside him – to save his life, the life of Secret Service agent Taft (Joel Kinnaman) and his country.