Mother has been briefed to create a campaign to drive awareness of the supercar rally as the brand expands worldwide.
This is the first time Modball has brought in an agency, and Mother will work on the account until October, with the potential to work on the 2015 event as well.
Mother, which was founded by PR consultant Lucy Heather in March 2014, won the work through a competitive pitch involving two other agencies.
The Modball group is responsible for rallies in Europe, the US and Australia. The opening event, The Modball Rally Europe start line and car display, will take place on Pall Mall in London on 21 June.
The route will take 150 sports cars on a seven-day journey covering 2,000 miles through Paris, Lyon, Barcelona, Valencia, Denia and the finish line in San Antonio Harbour, Ibiza.