ITV will acquire a 75 per cent stake in Boom Supervisory Limited, which owns Twofour and a number of other production outfits, for £55m initially.
The broadcaster bought the group, which has offices in the UK and the US, from majority shareholder LDC, the private equity arm of Lloyds Banking Group.
ITV has been reshaping its business to minimise exposure to volatility in advertising markets by boosting spending on original content, buying up production companies to help produce programmes it can sell around the globe.
In March it announced it would buy Talpa, the Dutch production company behind The Voice, in a deal that could cost up to £781m.
ITV said last year Twofour and the production outfits under its stable produced more than 1,200 hours of programmes. Hits include Posh Pawn and The Hotel Inspector.
An ITV spokesman said: “Our mission is to work with the best creative talent in Britain and our acquisition of Twofour is a brilliant illustration of that ambition.
“They’re a creative group at the top of their game across factual, entertainment, drama and comedy.”