Cormier defeated Miocic in July 2018 to claim the belt, winning via a vicious knockout in the first round, before the latter reclaimed his title a year ago.
The pair now meet for their highly anticipated trilogy fight, which will be the last of Cormier’s illustrations career.
In the co-main event, bantamweight ‘Sugar’ Sean O’Malley faces Marlon Vera. Elsewhere on the card, former heavyweight champion Junior dos Santos takes on Jairzinho Rozenstruik.
Here is everything you need to know:
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 underway 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)