Ryan Seacrest is expanding his growing media empire with his first acquisition in the marketing space.

The “American Idol” host is buying a majority stake in New York’s Civic Entertainment Group, a TV-focused marketing agency with client billings of around $40 million.

The move is part of Seacrest’s wider aim to build up a portfolio of assets under his Seacrest Global Group.

Seacrest, whose ventures include Seacrest Productions, has the backing of private-equity firm THL Partners along with Clear Channel’s Bob Pittman.

Civic is run by co-founders and co-CEOs Stuart Ruderfer and David Cohn. Ruderfer got his start in the Bloomberg administration, helping to attract events to New York, and was marketing director at the Parks Department.

Seacrest was advised in the transaction by LionTree Advisors, run by former UBS banker Aryeh Bourkoff.

Financial terms were not disclosed.