During Sony's PS4 announcement event, Gaikai head Dave Perry said that the new console will not offer native support for PS3 games out of the box.
Instead, Gaikai is developing a cloud service that could offer PS3 games on the new console without the built-in hardware compatibility.
"The technology is so advanced that some day we could easily stream PS1, PS2, PS3 and the PS Mobile games on any device, including the PlayStation 4," Perry added.
Prior to the announcement, Gaikai registered domains for the name PlayStation Cloud, which was rumored to be used for playing PS3 games on the new console. Those rumors turned out to be true.
Officially announced at the start of the event, the PS4 is compared to a "supercharged PC". It features an x86 CPU, enhanced PC GPU and 8GB RAM.
The Dualshock 4 controller, which was leaked before the event, appears similar in design to the standard PS3 controller, except for a touch pad, share button, and light bar that acts like a PlayStation Move.
New first-party games include Killzone Shadow Fall and Infamous: Second Son.
Square Enix announced a new Final Fantasy, which will be unveiled at E3, Ubisoft confirmed Watch Dogs for launch, Capcom teased a new game called Deep Down and Braid creator Jonathan Blow announced The Witness.
Blizzard, meanwhile, announced Diablo 3 for the PS3 and PS4, while Bungie revealed that the PS4 version of Destiny will feature exclusive content.
> Read our on-going coverage on PlayStation 4
> PS4 reveal video stream, live blog
Photo gallery - PlayStation 4's new camera and DualShock controller in pictures: