Filmmaker James Cameron and Titanic discoverer Robert Ballard are backing a bid by a group of British museums to acquire a collection of 5,500 artifacts from the sunken vessel.
The campaign aims to raise $20m (€17m) to buy items from a private American company that salvaged them from the wreck.
The director of the 1997 blockbuster film Titanic, starring Leonardo DiCaprio and Kate Winslet, said there are concerns that the collection will be broken up and sold priv- ately because the salvage company has filed for bankruptcy.
"That's why people who feel some protective role have stepped up and kind of linked arms," Cameron said.
"It's an incredible piece of history, an object lesson about human hubris.
"If it gets sold into private hands, it disappears. It would be broken up and could never be reassembled."
Cameron said his expeditions to the undersea site have made him feel a responsibility to honour those who lost their lives on the doomed voyage in 1912.
The objects include a section of the ship's hull and a bronze cherub decoration from the its grand staircase.
They were recovered from the wreck site during seven deep-sea expeditions between 1987 and 2004.
The bid for the artifacts comes from the Royal Museums Greenwich, Nat- ional Museums Northern Ireland, Titanic Belfast and Titanic Foundation.
The National Geographic Society has pledge $500,000 to help fund the project.
The bid was announced at Titanic Belfast, at the location where the ship was designed, built and launched.