The British boxer will look to reclaim his WBA, IBF, WBO and IBO world titles - having suffered a shock defeat to lose them to the Mexican in June.
Anthony Joshua and Andy Ruiz Jr. will hold the first of three news conferences on Wednesday in Diriyah, Saudi Arabia. Both fighters will be in attendance to promote their December 7 rematch in Riyadh, Saudi Arabia. It’ll be a full week of press conferences for the fighters. They’ll be meeting on Thursday in New York, and then on Friday in London.

When is the Ruiz vs Joshua ring walk?
It is good news for British fans that it will not be the early hours of the morning - like the first clash between the pair in New York.
Ruiz AJ 2 free stream fight will take place on Saturday, December 7 in Diriyah.
The ring walks will begin at 10pm UK time - that is 1am in Saudi Arabia.
How can I watch the fight?
The huge heavyweight clash will be shown live on Sky Sports Box Office.
This will be available for £19.95, with the full undercard and main event shown.
You can also live stream for the same price on your computer, mobile and tablet devices.
Who else is on the fight card?
Andy Ruiz vs Anthony Joshua is the only fight currently confirmed on the card.
Yet, the Brit has previously stated that he hopes there will be a women's bout in Saudi Arabia.
It would have been better for the U.S press conference to take place in Los Angeles, California rather than New York. Ruiz’s fan base is in Southern California, not New York. Joshua arguably has more boxing fans in New York than Ruiz. It doesn’t make sense at all for the press conference to take place there. If the idea is to create more subscribers to DAZN, Ruiz Joshua free stream then California where the U.S press conference should take place. It’s unclear whether Team Ruiz had any say so about the location for the U.S press conference. Ruiz may need to talk it up to keep boxing fans from falling asleep, because former IBF/WBA/WBO heavyweight champion Joshua (22-1, 21 KOs) could make it dull if he’s going to be using canned speeches.
Anthony Joshua faces a make-or-break rematch with Andy Ruiz Jr to reclaim his four world heavyweight belts in Saudi Arabia. The 29-year-old British star was stunned by Ruiz when the pair met at Madison Square Garden in June. Joshua was knocked down four times by the Mexican fighter – who was 25/1 with many bookies going into the fight – before the fight was called off in the seventh round. Boxing on TV: Check out the latest fights and upcoming bouts here Ruiz now holds the IBF, WBO, IBO and WBA (Super) Heavyweight title belts, but Joshua will be keen to grab them all back in one piece when the pair step back into the ring in December. RadioTimes.com has rounded up everything you need to know about how to watch Anthony Joshua v Andy Ruiz Jr.