The incumbent on the business is WCRS, which is repitching.
The agency, owned by Engine, picked up the King ad account in April 2014 after beating Karmarama and then incumbent Albion in a competitive pitch.
Last year, King set up a scented bouncy castle on the South Bank in London to promote new game Candy Crush Jelly Saga.
A TV spot featured a large mock-up of the game in which the jelly queen character danced off against a woman in rollerskates to Destiny’s Child’s Bootylicious.
Starcom handles King’s media planning and buying.
King was established in Sweden in 2003. The company confirmed the review.