The company behind brands such as Cathedral City, Country Life butter and Utterly Butterly, will be bought by Canadian company Saputo in a deal worth £975 million.
Saputo, which is one of the world's largest dairy companies, will pay 620p per share for Dairy Crest, giving it the near £1 billion valuation.
Saputo chairman and chief executive Lino Saputo Jr said: "We believe that under Saputo ownership, Dairy Crest will be able to accelerate its long-term growth and business development potential and provide benefits to Dairy Crest's employees and stakeholders."
The Canadian firm said all of Dairy Crest's products would continue to be manufactured in the UK, with management based in Surrey.
The chairman of Dairy Crest, Stephen Alexander, said: "The acquisition should enable Dairy Crest to benefit from Saputo's global expertise and strong financial position to fulfil and accelerate its growth ambitions.
"The businesses have strong shared values and the board is confident that Saputo's plans to invest in and grow the Dairy Crest business mean the proposed transaction is positive for all its stakeholders."