Both sides have agreed to the 185-pound matchup, sources said. The UFC 244 pay-per-view event will take place on Nov. 2 at Madison Square Garden in New York. The UFC has not yet announced a main event.
Till (17-2-1) has been teasing the possibility of a new weight class for months. The 26-year-old posted a photo of Gastelum to his Instagram feed last week, with a simple caption, "Let's go."
Fighting out of Liverpool, Till went undefeated in his first five years as a pro, elevating him to a 170-pound title shot against Tyron Woodley in September 2018. Woodley defeated Till via submission in the second round of that title bout. Till would go on to suffer a second consecutive defeat six months later in the form of a second-round knockout to Jorge Masvidal.
Till's struggles to make the 170-pound weight limit have been well documented in recent years. His coach, Colin Heron, recently told ESPN he was open to Till moving up in weight, but he wanted to get a better understanding of Till's lean body weight in between fights. That process ultimately resulted in Till's decision to move up.
Gastelum (16-4) is also a former UFC title challenger. He fought Israel Adesanya for the interim belt at UFC 236 in April and lost via unanimous decision. That five-round bout is on the short list for Fight of the Year.
Fighting out of Southern California, Gastelum, 27, earned a title shot by defeating Michael Bisping and Ronaldo "Jacare" Souza. Like Till, Gastelum is a former welterweight who occasionally struggled with the cut.
Current middleweight champion Robert Whittaker is scheduled to defend his belt against Adesanya in a unification bout at UFC 243 on Oct. 5 in Melbourne, Australia.