The Saturday night film is the cable network's most-watched documentary effort in nearly 10 years.
Beyonce proved a huge draw for HBO on Saturday night.
The intimate documentary about the singer, Beyonce: Life is But a Dream, pulled 1.8 million viewers during its inaugural outing at 9 p.m. ET. It's the largest audience for a HBO doc since Nielsen revised its method of measuring viewership in 2004.
The only other documentary to approach Beyonce's haul was previous record-setter When the Levees Broke: A Requiem in Four Acts. The Spike Lee miniseries about the devastation caused to New Orleans by Hurricane Katrina earned 1.7 million viewers in 2006.
Life is But a Dream's handsome haul pulled three times the ratings of recent first-runs for HBO's Sunday series Girls.