(Reuters) - Viacom Inc <VIAB.O> said on Friday that it had hired financial advisers to explore a merger with CBS Corp <CBS.N> following a proposal by Sumner Redstone's National Amusements Inc, a majority shareholder of both companies.

Morgan Stanley <MS.N>, Allen & Co and LionTree LLC were retained as advisers by the special committee of its board, Viacom said.

Reuters reported last month that Viacom had hired Morgan Stanley and LionTree LLC to review its capital structure.

Viacom, which owns Nickelodeon and MTV, formed the committee of six independent board members last month to evaluate the merger proposal.

Privately held National Amusements said last month that a merger would allow the combined company to respond aggressively to the challenges of the changing entertainment and media landscape.

National Amusements owns 80 percent of voting shares of both media companies.

Shares of CBS and Viacom were up slightly in morning trading.

(Reporting by Aishwarya Venugopal in Bengaluru; Editing by Sriraj Kalluvila and Anil D'Silva)