Sony will bring its key releases to the consumer event, including playable versions of Uncharted 3: Drake's Deception and Resistance 3.
The firm will join Microsoft as a sponsor, while Electronic Arts has been confirmed to exhibit Mass Effect 3 and Battlefield 3.
PlayStation marketing director Alan Duncan said: "We are delighted to support GAMEfest 2011, and thrilled to offer UK consumers the opportunity to be able to get hands-on with our latest lineup including the much-anticipated Resistance 3 and the sequel to last year's game of the year - Uncharted 3."
GAME's UK marketing director Anna-Marie Mason added: "With Sony on board as a headline sponsor, we are confident that our show is going to be a success.
"We know that attendees want to get hands-on with PlayStation products and we are delighted to bring Sony's key titles to UK consumers at our inaugural event."
Announced at the Video Game BAFTAs in March, GAMEfest will run from September 16 to 18 at Birmingham's NEC arena.
Tickets went on sale last month, with prices starting at £5 for attendees under 12 years old and increasing to £10 for those aged 12 and over.