The 30-second spot, the first created by DDB New York since winning the account from BBDO last year, features the rapper on his way to an awards ceremony when his car breaks down.
Diddy has to hitch a ride to the awards in a Pepsi truck and as he pulls up to the red carpet a host of celebrities, including Crawford and Longoria, marvel at his "cool" method of transport.
The ad is due to premiere during the US Super Bowl on February 6, traditionally the time when Pepsi debuts a significant new campaign.
The ad marks the first time P Diddy, real name Sean Combs, has promoted another brand other than his businesses Bad Boy Records, his clothing range Sean John, and two restaurants.
Original 80s supermodel Crawford starred in Pepsi's 1992 "new can" ad campaign created by BBDO. She has also endorsed cosmetics brand Revlon and American fur label Blackglama.
Langoria plays cheating housewife Gabrielle Solis in the critically acclaimed drama 'Desperate Housewives', which has secured excellent ratings in the US and UK since its launch.
Last December, PepsiCo shifted its $37m (£19m) US Diet Pepsi account out of its long-time advertising agency BBDO New York to sister Omnicom Group agency DDB New York. The P Diddy campaign is the agency's first piece of work since winning the account.
The latest celebrity studded commercial joins a long list of Pepsi ads, which have previously featured celebrities such as David Beckham, Jennifer Lopez, Beyonce, Enrique Inglesias, Pink and Britney Spears.
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