Rock Hudson, left, and Lee Garlington in Puerto Vallarta, 1963, as seen in Rock Hudson: All that Heaven Allowed (Warner Bros Discovery)

The filmmakers behind this illuminating and probing profile of closeted Hollywood star and inadvertent activist Rock Hudson’s screen career owes a huge debt to its team of researchers. They have uncovered atypical and presumably hard to find visual and audio material that brings the star-making machinations of 70 years ago into a frank light.

Director Stephen Kijak skimps on Hudson’s upbringing in Illinois and jumps to his arrival in Hollywood in the late 1940s after serving in the Navy. The period of the mid-1940s is coyly conveyed in photos of young men frolicking on the beach with Hudson. (Ostensibly, these black-and-white images have been in private collections. Chances are many a Facebook group will spring from the visuals from this documentary.) In another find, Kijak includes an interview of Richard Hodge, the nephew of Ken Hodge, a radio producer who had a relationship with Hudson in the late 1940s, when Hudson was hoping to find a way to break into show business.

Although he had no acting experience, Hudson, according to this biodoc, jumped at the chance to be represented by the talent manager Henry Willson, the subject of Robert Hofler’s 2005 book The Man Who Invented Rock Hudson. As a result, he dumped Ken and became part of Willson’s rotating casting coach. Hofler credits Willson for changing the greenhorn’s name from Roy Fitzgerald and teaching the budding actor how to pass as straight. Hofler is among the many informative voice-overs here, in addition to the likes of historian David Thompson, Hudson biographer Mark Griffin, actress/film buff Illeana Douglas, and director Allison Anders, who watches Hudson’s Giant at least once a year.

Hudson and his close friends George Nader and his lover Mark Miller are described as a hidden society as they went out to gay bars throughout the 1950s and into the ’70s, though they all remained closeted in public. Times have undoubtedly changed. In front of the director’s camera, only Hudson’s intimate friends and former lovers appear before the camera—including the star’s longtime boyfriend Lee Garlington. They spill the beans, providing plenty of intimate details about the star.

Actresses Kathleen Hughes, who screen tested with Hudson in 1949; Piper Laurie; and Linda Evans, all provide crucial perspectives on Hudson from many points of his career. Evans, who played Hudson’s love interest in the 1980s soap opera Dynasty, is among the most emotional and riveting voices as she recounts the filming of the scene in which her onscreen character is kissed by Hudson, who at that time had AIDS and would be dead less than six months after this particular episode aired in 1985. It was during that summer, under much media speculation about his noticeably gaunt physique, that his publicist Yanou Collart announced he had AIDS, and his secret was out.

In a way, friend and writer Armistead Maupin had already outed the movie star in his 1978 novel Tales of the City, though the actor’s fictional counterpart goes unnamed as “_____ _____.” During the late 1970s, Maupin took Hudson on a tour of a San Francisco sex club, where the movie star was recognized by many. (Armistead is among the many male talking heads who had a fling or two with the actor.)

His death from AIDS in October of 1985 brought more attention in the mainstream media to this medical crisis: He put a face to an epidemic. With his donation of $250,000, and spearheaded by friend/co-star Elizabeth Taylor, the American Foundation for AIDS Research was established. However, his good friend Nancy Reagan did not lend a helping hand when the American Hospital of France declined to treat the actor and airlines refused to transport him back to the States.

Additionally, Kijak traces the highs and lows of Hudson’s career, which includes his remarkable work with Douglas Sirk (All That Heaven Allows) and George Stevens’s Giant, for which he was nominated for a best actor  Oscar. At its best, the documentary describes the homophobia of mid-20th century America by those who lived through it, while also painting a picture of the gay subculture that thrived underground.

Rock Hudson: All That Heaven Allowed was among the dozens of world premieres at this year’s Tribeca Festival. Unlike so many such films that may take time to reach screens, big or small, this recommendation arrives on HBO June 29th.