Former ONE Championship two-division titleholder Reinier de Ridder has signed a deal with the UFC, the promotion announced Wednesday.

De Ridder will make his debut at middleweight against Gerald Meerschaert on Nov. 9.

De Ridder is one of the UFC's biggest free-agent signings in recent memory. The 34-year-old Dutchman spent five years in ONE, where he previously held the light heavyweight (225 pounds) and middleweight (205 pounds) titles.

De Ridder won his first seven fights under the ONE banner before dropping both belts to Anatoly Malykhin in back-to-back stoppage losses. De Ridder parted ways with ONE earlier in 2024 and got back in the win column with a first-round TKO at a UAE Warriors event in July.

"The Dutch Knight," who has been a pro MMA fighter since 2013, holds a 17-2 record with four knockouts and 11 submissions.