The world number 35 is the most high-profile signing for the 14-event league and joins two-time Masters champion Bubba Watson, Talor Gooch and Harold Varner III on the Range Goats team.
American Brendan Steele and New Zealand’s Danny Lee have also moved to the breakaway circuit ahead of its first event of the year, which gets under way in Mexico on Friday.
Pieters won a record four points on his Ryder Cup debut at Hazeltine in 2016, including all three matches with Rory McIlroy, who said at the time: “I’ve got a partner beside me for the next 20 years, I’m not letting anyone else have him.”
The 31-year-old had also hosted two tournaments on the DP World Tour in his native Belgium and was part of the winning Continental Europe team in the Hero Cup in January.
But his switch to LIV came just days after he complained on social media that he had not received an invite to the Genesis Invitational on the PGA Tour, despite his lofty position in the world rankings.
— LIV Golf (@livgolf_league) February 21, 2023
“In less than a year, LIV Golf has reinvigorated the professional game and laid the foundation for the sport’s future,” LIV Golf chief executive Greg Norman said.
“In 2023, the LIV Golf League comes to life. The most popular sports in the world are team sports, and our league format has already begun to build connections with new audiences around the globe.
“Major champions, current and future Hall of Famers, and up-and-coming stars are all committed to creating this new platform for world-class competition as the sport evolves for the next generation.”