(CNN) -- AOL has agreed to purchase The Huffington Post for $315 million, the two entities announced in a joint news release Monday.

"As part of the transaction, Arianna Huffington, The Huffington Post's co-founder and editor-in-chief, will be named president and editor-in-chief of The Huffington Post Media Group, which will include all Huffington Post and AOL content," the statement said.

The new group will have a combined 117 million unique visitors a month in the United States and 270 million around the world, according to the release, which cited December 2010 data from the marketing research company comScore.

"Our readers will still be able to come to the Huffington Post at the same URL, and find all the same content they've grown to love, plus a lot more -- more local, more tech, more entertainment, more finance, and lots more video," Huffington said in the statement.

The boards of directors of each company and shareholders of The Huffington Post have approved the transaction, but the proposed transaction is subject to customary closing conditions, including receipt of government approvals, the two groups said.

The transaction is expected to close in the late first- or early second-quarter of this year, according to the statement.