Perry Mason could prove a sleeper hit for HBO.

The legal-detective drama premiered Sunday night to the cable network's biggest series premiere ratings in two years.

Mason was watched by a total of 1.7 million viewers across all platforms — that's more than the comic drama Watchmen (1.5 million) or the Stephen King adaptation The Outsider (1.2 million).

With somewhat mixed-to-positive reviews and a more traditional feel than many of HBO's more edgy fare, the drama didn't seem like the likeliest series to pop out of the gate. In fact, HBO was for awhile calling Perry Mason a limited series and then switched its designation to a drama, opening the door to a renewal. If the show continues close to this level in the ratings, a pickup is all but assured.

Mason is a reboot of the classic CBS series that starred Raymond Burr in the 1950s-60s. The HBO version stars Matthew Rhys (The Americans) as a low-rent private investigator living check-to-check and is haunted by his wartime experiences in France who gradually finds a new purpose in the legal profession. The series also stars Tatiana Maslany (Orphan Black) as the leader of a Christian revival community, Chris Chalk (Gotham) a beat cop with a knack for detective work, and John Lithgow (Dexter) as Mason's mentor and sometimes employer.

Perry Mason season 1 is eight episodes and airs Sunday nights on HBO.

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