Kay, who presents Channel Four's T4 programme and hosts a weekend Radio One show, makes his debut as the Doritos ambassador with the launch of the Doritos Latino variant.
The TV execution, which breaks today, ditches the previous "friendchips" work and instead shows Kay bringing Latino spirit to a dull party.
The spot opens on a couple sitting silently on a sofa. Kay pops up behind them and says: "Flippin' heck, it's chilly in here. Let's bring out the Doritos. That should raise the temperature a bit."
He places a packet next to the girl, who starts eating them. She turns to the boy and confesses she has been "bonking" a bloke they met in Rio.
As they share the crisps, the boy also admits he has been secretly seeing someone.
Suddenly their two lovers appear from out of the sofa and start a Brazilian-style party, complete with dancing girls in flamboyant costumes, which Kay and others join in. Kay says: "I love a Brazilian, me." The endline reads: "Get Doritos. Get together."
The ad was written and art directed by AMV's executive creative director, Peter Souter. The director was Paul Weiland through The Paul Weiland Film Company.
Doritos' senior brand manager, Corinne Prior, said: "We are really excited to have Vernon on board. He is a fun and lively person for a young, irreverent brand and is the ideal face of Doritos: a sociable guy for a sociable brand.
"As this year is our tenth anniversary, we have changed the campaign completely. It's the end of the cult TV programme Friends and the end of our Doritos 'friendchips' campaign."
Media planning and buying was handled by OMD UK. The target audience is 18- to 35-year-olds. The TV ad will run on satellite and terrestrial channels including Sky, ITV and Channel 4.