Champion Miocic lost his belt to Cormier in July 2018 after being knocked out late in the first round, but the American won back his strap in August 2019 by TKOing his compatriot in the fourth round.
Now the pair compete against one another for the third and final time, at the UFC’s Apex facility in Las Vegas, with many believing that the victor can rightfully be labelled the greatest heavyweight in MMA history. Cormier, 41, has said he plans to retire regardless of the result.
Here’s everything you need to know about UFC 252:
When is the event and what time does it start?
UFC 252 takes place on Saturday 15 August in Las Vegas, but for UK fans it kicks off in the early hours of Sunday morning.
The preliminary card will get under way at 1am BST on Sunday, with the main card following at 3am BST. The main event between Miocic and Cormier is expected to begin at around 5am BST.
How can I watch it?
The event will air on BT Sport 1 in the UK, and subscribers can also stream it live on the BT Sport website and app.
In the US, UFC 252 will be shown on ESPN+.
Stipe Miocic (C) vs Daniel Cormier (heavyweight title)
Sean O’Malley vs Marlon Vera (bantamweight)
Junior dos Santos vs Jairzinho Rozenstruik (heavyweight)
John Dodson vs Merab Dvalishvili (bantamweight)
Herbert Burns vs Daniel Pineda (featherweight)
Jim Miller vs Vinc Pichel (lightweight)
Felice Herrig vs Virna Jandiroba (women’s strawweight)
TJ Brown vs Danny Chavez (featherweight)
Ashley Yoder vs Livinha Souza (women’s strawweight)
Early prelims (11.30pm BST, Saturday 15 August)
Chris Daukaus vs Parker Porter (heavyweight)
Kai Kamaka vs Tony Kelley (featherweight)