Sekonda is planning to launch a higher-priced brand, called XS, at the end of the year, and Rocket will work alongside Campbell Doyle Dye to develop and implement the communication strategy.
The win comes less than a year after Time Products, the owner of Sekonda, underwent a management buyout worth £80 million. Since then the company has revamped its products and brand identity.
In March, CDD was appointed to handle the creative account. A print campaign breaks next month.
Sekonda's most famous advertising was its "Beware of expensive imitations ads through Gold Greenlees Trott in the 90s.
In 1995, the account moved to M&C Saatchi, which changed tack and used the line "Time is precious. It doesn't have to be expensive and promoted the watch brand on the basis of value as opposed to its low cost. CDD won the brief from Toybox.
Mark Holden, the creative director at Rocket, said: "We are working from a very solid business base as Sekonda is the largest UK watch brand in terms of volume sales - we will be looking for ways of increasing value share."
Mediaedge:cia previously handled the media account for Sekonda.
Julian Pollock, the marketing director of Time Products, said: "Rocket impressed me with its insight into the role of communication for building brands."