The agency has devised eight press ads which will appear to coincide with the end of British Summer Time on 27 October.
The ads use a variety of risque straplines to emphasise the campaign's message.
The ads will run in the November issues of monthly magazines, and will also appear in weeklies from the end of October.
The campaign will run in conjunction with an on-pack promotion, called the Horlicks Sleep Challenge. Consumers also get a free sleep pack from promotional packs and can visit a website for sleeping tips.
The Sleep Challenge ads use the straplines "Improve your performance in the sack", "10/10 in bed" and "What you've always wanted in bed".
The clock-change reminder ads feature straplines such as "So, your extra hour in bed. How was it for you?", "The clocks are changing. What will you get up to in your extra hour?" and "Fulfilment in the bedroom at last".
The drive comes two years after GlaxoSmithKline spent £3 million on Horlicks, positioning it as a "sleep expert". The rival brand Ovaltine returned to TV last year for the first time in 14 years with a campaign showing the brand's energy-giving properties.
The Horlicks ads were written and art directed by Sarah Gard and Chris Rutter, with the hand lettering designed by Alison Carmichael. Media was planned and bought by MediaCom.