Fox’s Tuesday night laffers are dusting off an old sitcom custom in a bid to remind viewers that the genre still has legs.

Both “Back to You” and “‘Til Death” have added a voiceover at the start of each episode that tells auds the series is “taped in front of a live studio audience.” Each show’s thesps will take turns making the announcements.

Fans of 1970s and early 1980s sitcoms remember the line, which came as the first scene unfolded on shows such as “Happy Days” and “Cheers.” But most shows dropped the practice by the 1990s, as it seemed almost corny — and auds tended to understand that for the most part, those were real people laughing at the jokes.

But with the sitcom on life support for much of this decade — and filmed, single-camera comedies getting most of the attention — the producers behind Sony Pictures TV’s “‘Til Death” came up with the idea of bringing back the slogan.

Fox current programming exec VP Marcy Ross said “‘Til Death” exec producer Josh Goldsmith first arrived at the notion after growing tired of hearing complaints that the show’s “laugh track” was too juiced. After telling one too many viewers that it’s a real, live, excited audience, he approached Sony and Fox over the summer. The network then brought up the idea to the producers behind “Back to You,” who sparked to it as well.

“We thought it was a great idea, especially with all the discussions in the press about whether the format is dead, or if audiences will still watch comedies,” Ross said. “The writers and creators of these shows are so committed to making the comedy be alive and accessible. They want to will the sitcom back to life.”

Ross does admit that sometimes audiences get a little too rowdy — which is why sitcom laughter frequently sounds like it has been enhanced. To combat that problem, she said the net is paying more attention to who’s warming up sitcom crowds and making sure the studio audience is engaged in the show and not responding to the warm-up performer’s antics.