The smaller sized bottle will be available from April with a recommended retail price of £7.49.
“The average basket spend within convenience is £11.13, so the new 35cl allows consumers to choose a summer spirit option within this price bracket,” said assistant brand manager Francesca Miles.
"By launching the new bottle size early in the season, it allows retailers to drive repeat purchase of Pimm's throughout the summer, particularly on impulse occasions such as St.George’s Day and bank holidays," she added.
The launch will be backed by a £50,000 marketing spend.
Diageo has also earmarked £1.6 million to support its Bring Home the Spirit of Summer campaign. The push is designed to connect with consumers when they are planning what drinks to mix at home after work and will include ads at railway stations, in the London Underground, on drive-time radio slots and in London’s consumer press titles.
Consumers will be targeted at city centres, train stations and shopping centres between 3pm and 8pm, with “summer spirits squads” giving out limes to be used in long drinks and recipe cards.
Digital and radio ads will promote a competition encouraging listeners to pick a song which defines the summer spirit, with the results played in an afternoon-long radio show during the August bank holiday weekend.