The BBC, which produces the show, appointed Anomaly London after a competitive pitch that took place at the end of 2015.
Anomaly is tasked with creating a global integrated campaign to promote the show ahead of its return – with new hosts Chris Evans and Matt Le Blanc – in the summer.
Stuart Smith, the chief strategy officer and partner at Anomaly, said: "Anomaly exists to tackle big business challenges. Top Gear is one of the planet's most loved shows, and it has history, so helping re-launch it is a task we're relishing."
In 2013, The Guinness Book of Records named Top Gear the world’s most widely watched factual TV show.
Jeremy Clarkson, James May and Richard Hammond hosted the show until 2015 when Clarkson was sacked for what the BBC described as an "unprovoked physical and verbal attack" on a Top Gear producer.