The contest - which will have a maximum field of 14 and be free to run in and enter - will see the winner receive $10m, with horses down to 10th place sharing another $10m between them.
Details were announced at a launch event in Saratoga by Prince Bandar bin Khalid Al Faisal, chairman of the Jockey Club Of Saudi Arabia, who said: "The introduction of the Saudi Cup as an international race is without doubt the most significant event in the history of horseracing in Saudi Arabia, and demonstrates our resolve to develop this great sport in the Kingdom of Saudi Arabia, and also our ambition to become a leading player on horseracing's world stage.
"We look forward to welcoming international horsemen and women, the media, racing enthusiasts and the public to Riyadh in 2020."
Frankie Dettori is among the jockeys to have ridden at King Abdulaziz Racetrack over the past few years.
He said: "I've been going to King Abdulaziz Racetrack ever since it opened. It's based on Belmont, in that it's a one-turn mile and a quarter. Of all the dirt tracks I've ridden, it's the one I like best, as you can win from the front, and you can win from behind - it's a fair track.
"The other thing I like is that the kickback is so much less than on other dirt tracks. I don't know why, but the sand seems finer and doesn't stick. You only need a couple of pairs of goggles, where on other tracks you need four or five.
"It's a kinder track that I can see turf horses handling."
Top French jockey Olivier Peslier said: "King Abdulaziz Racetrack is one of the best dirt tracks in the world. A wonderful track and I know that the American jockeys like it very much because it really suits the American horses.
"It has a long straight and there is not much kickback."
The Jockey Club of Saudi Arabia will arrange and fund the shipment of all invited horses, and arrange and pay for the flights and hotel accommodation of the horses' connections.
Further international races will be staged on the undercard.
