The heavyweights square off in a main-event fight at Wembley Arena, where Joyce last took to the ring.
The Briton (13-0, 12 knockouts) defeated Carlos Takam in the sixth round last July, while 34-year-old Hammer is looking to build momentum following his first-round knockout of Drazan Janjanin in May.
German Hammer (27-9, 17 KOs), a former opponent of Tyson Fury, seems to stand between Joyce, 36, and a clash with Joseph Parker – a bout that could take place later this year.
Here’s all you need to know.
When is it?
The fight will take place at Wembley Arena in London.
The main card will begin at 7pm BST, with ring walks for the main event expected to start at around 11pm.
How can I watch it?
The event will air live on BT Sport in the UK, with subscribers also able to stream the action live on the broadcaster’s website and app.
Joyce – 1/50
Draw – 33/1
Hammer – 16/1
Joe Joyce vs Christian Hammer (heavyweight)
Jason Cunningham (C) vs Zolani Tete (Commonwealth super-bantamweight title)
Callum Johnson vs Igor Mikhalkin (light-heavyweight)
Nathan Heaney vs Nizar Trimech (middleweight)
Mark Chamberlain vs Marc Vidal (lightweight)
Micky Burke vs Serge Ambomo (super-welterweight)
Henry Turner vs Jakub Laskowski (super-lightweight)
Tommy Fletcher vs Darryl Sharp (cruiserweight)
Arnold Obodai vs TBA (cruiserweight)