The account, which was previously handled by Mindshare, moves after a review process. The Engine-owned consultancy Edwards Groom Saunders will continue to handle media planning.
The7stars has acted quickly to replace its William Hill account, which is moving out of the agency after it declined to take part in a pitch that was called last month.
Matt Prevost, the marketing director of Gala Coral, said: "Appointing the7stars was an easy decision for us to make – the agency has a solid track record in the gambling and betting sectors, and we have been impressed with their work for some time."
Liam Mullins, the head of press at the7stars, said: "Gala Coral Group are one of the biggest names in the UK betting and gambling markets, and we are proud to be working with them."