Lexis PR, Trimedia UK and start-up Van Communications are in the running for the brief, with a decision expected within weeks.
The three agencies already work for various Diageo brands - but the remit up for grabs, described by a source close to the pitch as 'very big' - is a fresh cross-category PR job.
Diageo GB head of brand PR Clare Fleerackers confirmed the agencies had pitched for a brief spanning Diageo's gin, whisky and vodka brands. She declined to provide further details.
Lexis already works with Diageo on Baileys, Blossom Hill and Guinness; Trimedia handles Pimm's, Gordon's and Johnnie Walker; Van, meanwhile, has a roving PR brief across brands already worked on by other agencies.
The pitch list is an intriguing clash of agencies - Van is run by Mark Cooper and Matt de Leon, both former Lexis staff, while its executive chairman is Lexis co-founder Tim Adams.
Diageo has pledged to focus its marketing activity on global priority brands such as Smirnoff vodka.