LOS ANGELES, (Reuters) – Burger King Holdings Inc  agreed to sell itself to investment firm 3G Capital for $3.26  billion, giving the No. 2 U.S. fast-food chain breathing room  to fix its business and close the gap with leader McDonald’s  Corp.

At $24 per share, the offer represents a 46 percent premium  to Burger King’s price before news of the negotiations emerged  on Wednesday.

“It was a call out of the blue,” Burger King Chairman and  Chief Executive John Chidsey told Reuters in an interview when  asked about how the talks started. He declined to give  additional details.

Chidsey will keep his roles during a transition period and  then become co-chairman with 3G Managing Director Alex Behring.

The sale, worth about $4 billion including debt, is  expected to close in the last three months of 2010. Burger King  has until Oct. 12 to solicit a richer offer from other buyers.