(Reuters) - Cloud service provider Box Inc <BOX.N> said on Monday it would appoint three new directors to its board as part of an agreement with activist investor Starboard Value LP.

Starboard is currently the third-largest shareholder in Box with a 7.7% stake, following Vanguard Group and BlackRock, according to data from Refinitiv.

While Jack Lazar, former chief financial officer of GoPro <GPRO.O>, will join Box's board immediately, a second director will be selected from a list of candidates provided by Starboard, the company said in a statement.

The company's board will choose a third director ahead of its annual meeting of stockholders in June, it added.

Two of Box's current board members, including Chief Financial Officer Dylan Smith, will not stand for re-election, while one board member will retire, Box said.

Starboard first revealed a stake in Box in September and said it might talk to the company about exploring a sale, as well as on operational improvements.

Box has also formed a committee to work with its management to suggest ways to improve growth and margin.

"We see a number of opportunities for substantial shareholder value creation ...," Starboard's managing partner, Peter Feld, said.

(Reporting by Supantha Mukherjee in Bengaluru; Editing by Anil D'Silva)