White revealed the date to Fox Sports on Friday. MMAJunkie.com first reported the bout was in the works for the spring. The event does not yet have an official location.
Gaethje (18-1) is coming off his first professional loss to Eddie Alvarez at UFC 218 last month. A former WSOF champion, Gaethje won his UFC debut in spectacular fashion against Michael Johnson last summer, but he suffered a knockout loss in his second appearance.
Fighting out of Denver, Gaethje has finished 15 of his 18 career wins via knockout.
Poirier (22-5) is coming off a third-round submission win over Anthony Pettis in November. The American Top Team fighter wanted a bout against Alvarez, whom he fought to a no-contest in 2017, but Alvarez wasn’t interested in the potential rematch.
ESPN.com ranks Poirier and Gaethje the No. 5 and No. 9 lightweights in the world, respectively.