Their differences extended down to their dogs. Dwight, a perfectly poof-y white Coton de Tuléar, stays with the elegant and eternally camera-ready Debbie. But good luck keeping your eyes off Gary, the dark, panting bulldog with his slobbery tongue drooping out of the side his mouth. Gary was forever in Carrie’s arms, on her side of the Reynolds-Fisher compound where the legendary Hollywood mother-daughter team lived and laughed during their final years.

It’s impossible to watch Alexis Bloom and Fisher Stevens’ warm documentary Bright Lights: Starring Carrie Fisher and Debbie Reynolds right now without reflecting on the shocking late December deaths of its two subjects. HBO had intended to air the film (which played some of the major festivals last year) in spring, but the channel is correct in its decision to bump up the date. Cynics might say the network is capitalizing on a hot topic, but the film makes its own argument. These were two women who reached a state of balance thanks to an almost aggressive honesty. Their lives were on display anyway (“We are always on a red carpet,” Fisher tells reporter who asks what they do when they aren’t on a red carpet), so why not shed some light when interest is at its peak?

Debbie Reynolds, allegedly retired, lived in golden-hued glamour down the hill from Carrie Fisher’s Pee-wee’s Playhouse-esque kitsch pavilion, a perfect embodiment of her quick wit and survivor’s sarcasm. (The shower curtain with the Psycho bloodstain handprints is my personal favorite.) The plot of Bright Lights is almost in reality television territory. Basically, we’re privy to various “days in the life”. There’s preparation for one of Reynolds’ Vegas nightclub acts, and travelling with Fisher to a Star Wars-related “lap dance session” – what she calls the quick autograph/photo op cash transactions that bring in a nice revenue stream.

Luckily, there is an inherent gravitas at play, and not only because of the recent tragedy. These women meant a lot to their respective fans, and the footage wisely includes a good deal of directorial coloring outside the lines. Among the best sequences is a fairly standard interview interrupted by an errant burglar alarm. Reynolds and Fisher lightly zinging one another as they blaze through the newest obstacle of the day has shades of the great American documentary Grey Gardens, but its melancholy doesn’t share the same decay or underachievement. Fisher is shown getting in shape (begrudgingly) for a return to Star Wars, and the ailing Reynolds does well accepting a lifetime Screen Actors Guild award, even if, during the limo ride, it seems like she won’t be able to string two sentences together.

Reynolds was well aware of her place in the Hollywood pantheon, and maintained a rich appreciation for collecting memorabilia. No one thinks it strange that she owns a piece of furniture that belonged to Elizabeth Taylor – the woman who notoriously “stole” Reynolds’ one true love, Fisher’s father, Eddie. Similarly, there is no mention that one of Fisher’s remaining vices is a ubiquitous can of Coca-Cola, for which her late father was a famous pitch man.

There is an uncomfortable sequence in the film, shot in 2010, in which Fisher visits her quite ill father, who was absent during most of her childhood, and just lays it out: “I was funny because I thought you’d want to be around me.” It’s a heavy scene, and old home movie footage is dripping in heartache and loss. Clips from Postcards From the Edge, the Mike Nichols film based on Fisher’s quasi-memoirs (written when she was “very angry”), loom like the memories of a bad fight to remind us of less harmonious times.

But Fisher, her mind forever twelve steps ahead, always snaps it back with a joke, and the spine of Bright Lights is a strong two-hander comedy between veteran show-folk. Self-deprecating bon mots, wordplay, song lyrics and perfectly timed occasional moans are what elevate this beyond simple “Keeping Up With” material. The highlight, old film of Reynolds decked out in Bob Fosse-style spangles introducing pre-Princess Leia Fisher to sing Bridge Over Troubled Water, proves that they really don’t make stars like they used to.