HELSINKI, April 17 (Reuters) - Japan's Sega Sammy Holdings Inc (6460.T) has agreed to launch an offer for Finland's Rovio Entertainment (ROVIO.HE), the maker of the Angry Birds mobile game, for 706 million euros ($775.8 million), the companies said in a joint statement on Monday.

Tokyo-based Sega will offer 9.25 euros per share for Rovio, a 19% premium over Friday's closing price of 7.775 euros.

Rovio, which has been conducting a strategic review, on Saturday said it was in talks with Sega over a possible tender offer. The Wall Street Journal had reported on Friday that a deal between the two companies was imminent.

Israeli peer Playtika (8II.F), had made a preliminary bid in January to buy Rovio for 683 million euros, but the Angry Birds maker confirmed last month talks had ended.