NASHVILLE (AP) — Sportsbooks are set to accept the first bets in Tennessee's unique online-only sports betting program starting early Sunday, the Tennessee Lottery announced Friday.

Three of the four initial operators — DraftKings, FanDuel and BetMGM — have completed all the requirements to launch Sunday, according to the lottery, and each has said it is ready for a day-one start.

The lottery said the fourth operator, Tennessee Action 24/7, has system testing planned for Saturday. The Tennessee-based sportsbook plans to start up Sunday, said Tennessee Action 24/7 President Tina Hodges.

A flurry of advertising has already begun ahead of the start of sports betting in Tennessee, which companies can offer starting at 12:01 a.m. Central time before Sunday's NFL games. The kickoff comes more than a year and a half in the making.

Sports betting barely passed in Tennessee in spring 2019, and Republican Gov. Bill Lee let it become law without signing it due to his opposition to more gambling in a state without casinos. After the law took effect that summer, plenty of legwork followed for the lottery, which was tasked with coming up with rules and vetting operators and others looking to get into Tennessee's industry. Now, the lottery will regulate how sports betting is carried out.

"This Sunday will represent the culmination of an enormous amount of work and due diligence to bring online-only sports wagering to Tennessee, the only state in the nation to do so," lottery President and CEO Rebecca Hargrove said in the release.

Three additional operators have applied to run sportsbooks in Tennessee: Wynn Resorts, William Hill and Churchill Downs, said lottery spokesperson Dave Smith.

Sports betting in Tennessee is restricted to people 21 and older who are physically in the state when they place bets. Under the law, 80% of privilege taxes collected for sports betting will go into the lottery for education account, 15% to local government infrastructure projects and 5% for mental health and substance abuse services.

Sportsbooks have already begun jockeying for Tennessee bettors' business, with various promos for bettors and marketing pushes through billboards, TV commercials and social media ads.