The fight will have a 210-pound catchweight limit and the promotion has yet to finalize a date or location for the event.
Ortiz last stepped in the cage in November, knocking out Chuck Liddell in the first round at Golden Boy Promotions's first MMA show. The 44-year-old has only fought sporadically since leaving UFC in 2012.
During his time in UFC, Ortiz was one of the promotion's biggest stars, winning the light heavyweight championship in 2000, and his rivalry with Liddell was legendary.
UFC inducted Ortiz into its Hall of Fame in July 2012.
Fans know Del Rio primarily from his wrestling career. He was a two-time WWE champion and held the World Heavyweight Championship on two occasions as well. He was also the GFW global champion for Impact Wrestling.
Long before he stepped inside the squared circle for WWE, though, Del Rio was a seasoned MMA fighter. He carries a 9-5 record into his bout with Ortiz, though his last official fight was in February 2010 and came in a losing effort to Yamamoto Hanshi.