Diageo Great Britain is to spend more than £2m to ensure Pimm's is the drink of choice this summer.
The marketing campaign, launching on April 17, uses radio and press advertising and a new TV campaign featuring the brand's iconic Harry character and 'Pimm's O'Clock' strapline.
From May to July the company is launching its biggest sampling campaign to date in major stores.
Marketing manager Matt Hunt said: "Last year saw the highest sales yet and we are confident retailers can again benefit from strong sales."