"CalSTRS believes the addition of Peltz to the board is best for P&G, the CalSTRS fund and ultimately, the teachers of California," CalSTRS Director of Corporate Governance Anne Sheehan said in a statement.

The U.S. public pension fund holds close to 5.6 million shares of P&G stock valued at about $508 million, and has been an investor with Trian since April 2011, the fund said in a statement.

P&G could not be immediately reached for comment outside regular business hours.

(Reporting by Munsif Vengattil in Bengaluru; Editing by Richard Chang)