Viacom has appointed Bob Bakish as acting president and CEO, effective on 15 November.
He will succeed Tom Dooley, who is leaving the company after less than two months at the helm.
Bakish, who has led Viacom's international business over the past ten years, will focus on investing in and developing new content, expanding distribution and pursuing strategic growth opportunities in Viacom's core businesses.
"Bob's record of innovation and achievement at Viacom, combined with his strategic vision and leadership ability, make him highly qualified for this position," said Tom May, chairman of the board.
"We are determined to move forward aggressively to strengthen Viacom for the future, whether as a stand-alone company or in a potential combination with CBS.
“There is a great deal of opportunity ahead and Bob is a superb leader to drive this effort, fully empowered to take the actions necessary to position Viacom for success."
Bakish joined Viacom in 1997 and has held leadership positions throughout the organisation, most recently serving as president and CEO of Viacom International Media Networks (VIMN), and its predecessor company MTV Networks International, since 2007.