While UFC 225 has yet to have a main event announced, the UFC’s return to Chicago is set to receive a potentially massive co-main event.

According to Dutch site MMADNA.com, Alistair Overeem will take on fellow top five ranked heavyweight Curtis Blaydes at the June 9th event. Both Overeem and Blaydes have hinted at an imminent fight announcement through their social media accounts in recent days.

Overeem (43-16, 1 NC) will head into UFC 225 coming off of a knockout loss to Francis Ngannou after having rebounded from a failed title challenge in 2016 with back-to-back victories over Mark Hunt and Fabricio Werdum. The 37-year-old Dutch fighter has held heavyweight world titles in both the defunct Strikeforce and DREAM promotions while also won the K-1 kickboxing Grand Prix in 2010.

Blaydes (9-1, 1 NC) meanwhile has gone unbeaten with one no-contest since losing his UFC debut to Francis Ngannou in April 2016 and most recently defeated Mark Hunt at UFC 221. The 27-year-old has scored 29 takedowns in the UFC thus far, the second most in promotional heavyweight history, and will most likely have the opportunity to cement a heavyweight title shot against Overeem in his home city come UFC 225.

UFC 225 is also currently slated to see Claudia Gadelha vs Carla Esparza, Joseph Benavidez vs Sergio Pettis and the return of former WWE star CM Punk.