The appointment sees media for Rubicon, which has previously been handled through Four Communications, consolidated at PHD North with other AG Barr brands, such as Irn Bru and Orangina.
Drum PHD, PHD's content and sponsorship agency, is also working on the business and has brokered a deal for Rubicon to sponsor a 'Summer of Cricket' on Sky Sports.
This year, AG Barr plans to spend £5m on marketing support for the Rubicon brand, and the cricket sponsorship will open with support of Sky's coverage of the upcoming ICC World Twenty/20 tournament in the West Indies.
The Sky cricket sponsorship will be supported by in-store activity and a range of cricket-related activity throughout the year.
Jason Spencer, managing director of PHD North, said: "The Sky sponsorship, coupled with other marketing activity across the year, gives us a great platform to deliver pioneering work for an ambitious client."