The restaurant chain is using Frank PR to handle a project to search for new musical talent led by jazz performer Jamie Cullum, who himself was first spotted at the PizzaExpress Jazz Club.
The Big Audition is open to all musicians and bands, with the winner's voice set to feature inside thousands of 'singing' takeaway pizza boxes.
Frank is handling the campaign on a project basis and has worked on a number of consumer projects with the brand in the past. PizzaExpress also uses Unity for consumer PR campaigns.
The firm is especially targeting 'young socialisers' and looking to leverage its musical heritage.
PizzaExpress has been associated with music, particularly jazz, since founder Peter Boizot opened the PizzaExpress Jazz Club in Dean Street, Soho, in 1971.
The public will be asked to vote for their favourite act later in the year as the top 50 acts perform at live regional heats. After the field is narrowed down, five acts will perform at a live final in November.
The firm, along with Barclaycard Freedom, will award the winner £5,000 to help kick-start their career.
The brand chose Cullum as the face of the campaign due to its long history with the artist. Cullum started his career performing three or four times a week for £50 and a pizza at PizzaExpress restaurants all over London.
He said: 'There are so many brilliant performers out there with genuine talent that never get the chance to be heard, so I'm really proud and excited to be part of this search.'
Meanwhile, Frank has picked up a retained consumer brief with Swiss mechanical watch manufacturer Oris. The brand, which dates back to 1904, has a strong association with Formula 1 motor racing and has been one of the sponsors of the AT&T Williams Formula 1 team for the past eight years.