'They Both Die at the End' will be penned by Chris Kelly.

As he fields offers for massive overall deals, J.J. Abrams continues to expand his TV empire.

Abrams' Bad Robot is teaming with HBO for the half-hour sci-fi comedy They Both Die at the End. The project, which is in development, is based on the book of the same name by Adam Silvera.

Set in the near-future where everyone receives a bureaucratic phone call notifying them at the start of their last day on Earth, They Both Die at the End follows a seemingly disparate group of people as they live their scary, funny, weird, hopeful, romantic and unexpected final hours, all connected through the two teenage boys at the heart of the New York Times best-selling novel on which it is based.

Chris Kelly (The Other Two) will pen the script and executive produce alongside Bad Robot's Abrams and head of television Ben Stephenson. The company's Rachel Rusch will co-exec produce.

The potential series hails from Warner Bros. TV, where Bad Robot is currently under an overall deal. Warners is but one of multiple media behemoths who are making massive offers to land Abrams and Bad Robot in what could be a groundbreaking mega-deal.

Should They Both Die at the End move to series, it would join a Bad Robot scripted slate that also includes HBO's Westworld and the upcoming Lovecraft Country and Demimonde (the first series Abrams is writing since Alias); the Hulu anthology Castle Rock; and the Apple half-hour dramedy Little Voice and drama My Glory Was I Had Such Friends, a limited series on which Abrams will reunite with former Alias star Jennifer Garner.

Former Saturday Night Live head writer Kelly, meanwhile, has had a banner week. His Comedy Central series The Other Two — which launched to critical praise — was renewed Monday for a second season less than a month after its debut. Kelly is repped by WME and 3 Arts.

Abrams is with CAA and Jackoway Austen.