U.S. private equity firm KKR plans to form a joint venture with pipeline company Williams Cos to buy oil and natural gas provider Discovery Midstream from private equity firm TPG Growth for about $1.2 billion.

KKR said it will fund the deal primarily through its energy and infrastructure funds.

Williams will also fund additional capital, when required, to bring its total ownership of Discovery to 50 percent.

KKR will own 60 percent stake in Discovery and the remaining will be held by Williams upon close of the deal, expected in the third quarter of this year.