ValueAct, which owns about 5.9 percent of Fox's Class B shares, and Fox also entered into a "standstill" agreement, Rupert Murdoch-controlled Fox said.

Fox said the agreement prevents ValueAct from solicit proxies against Fox, raising its stake above 7 percent or selling its stake to any person or entity that would boost the buyer's stake in Fox to more than 5 percent.

With Ubben's appointment, the size of Fox's board will increase to 13 from 12, the company said.

ValueAct, a hedge fund known for taking stakes in companies and quietly affecting change over the long term, took a $1 billion stake in Fox in August last year.

Fox's shares were up 1.1 percent at $25.47 in morning trading on Tuesday.

(Reporting by Lehar Maan in Bengaluru; Editing by Savio D'Souza)