An exhaustively researched feature documentary about “Lord of the Rings” star Ian McKellen has been acquired by Trafalgar Releasing for the U.S., U.K., and Scandinavia.

“McKellen: Playing the Part” is built around 14 hours of interviews with the legendary actor and has a raft of never-before-seen archive material, including behind-the-scenes footage from film and stage. The authorized documentary covers his early years, with access to diaries and private photo albums, his acting career, and his role in the gay rights movement.

Trafalgar, formerly known as Picturehouse Entertainment, will release “McKellen: Playing the Part” in the U.K. and Scandinavia this spring and in the U.S. later in the year.

In the documentary, McKellen delves into his film work and roles, including Magneto in the “X-Men” franchise and Gandalf in “Lord of the Rings.” The film features dramatic re-creations starring Luke Evans, Frances Barber, Adam Brown, Scott Chambers, Milo Parker, and Edward Petherbridge.

Joe Stephenson (“Chicken”) directed the film. “It was always my intention to make this documentary for theatrical release, to find a way to celebrate the life of one of our greatest actors on the big screen, so I’m delighted to be working with Trafalgar to give audiences the chance to see it as intended with a unique and exciting release,” he said.

The film is a B Good Picture Company production, produced with Surreal Film Company in association with Ugly Duckling Films and Blue Topaz Productions Ltd., with the support of Great Point Media and Lipsync Productions. International sales are handled by Independent, which did the deal with Trafalgar.

Trafalgar’s recently promoted director of distribution, Alice De Rosa, said: “We are excited to be working with director Joe Stephenson and his team on this fantastic film, bringing to life the story of Ian McKellen with an unprecedented amount of access to the acting legend.”