Pettis (24-10) spent 10 years as a fighter for the UFC, where he defended the lightweight title once after winning it in 2013.
Pettis fought three times in 2020, going 1-2 in those matchups (a loss to Carlos Diego Ferreira before wins over Donald Cerrone and Alex Morono). After starting his career 18-2 as a professional fighter, however, Pettis has gone just 6-8 since, including losses to Max Holloway, Dustin Poirier, Tony Ferguson and Nate Diaz.
The 34-year-old Pettis will face the 27-year-old Collard (18-8), who spent parts of 2014 and 2015 in the UFC and the past two years as a professional boxer.
Other lightweight matchups for the April 23 event will include Natan Schulte vs. Marcin Held; Olivier Aubin-Mercier vs. Joilton Lutterbach; Johnny Case vs. Loik Radzhabov; and Akhmed Aliev vs. Mikhail Odintsov.
Featherweight matchups will include Lance Palmer vs. Bubba Jenkins; Movlid Khaybulaev vs. Jason Soares; Brendan Loughnane vs. Sheymon Moraes; and Sung Bin Jo vs. Tyler Diamond.
The promotion will air on ESPN2.