Also spotted Tuesday night at the glitzy event at the Royal Albert Hall were the film's writer-director-producer James Cameron and his wife, actress Suzy Amis, who played a supporting role in the blockbuster about the real-life doomed luxury liner, which hit an iceberg and sank on its maiden voyage in 1912, killing more than 1,500 people.
Noticeably missing from the movie's 3D premiere Tuesday were the film's leading man Leonardo DiCaprio, who played Jack, and the late Gloria Stuart, who played the older version of Winslet's character, Rose. Stuart died in 2010 at age 100.
"The big thrill of it isn't just the 3D," Cameron told the BBC about the film's re-release. "It's bringing it back to the big screen, where it has a lot more emotional impact."
"People have been saying to me all day, 'How does it feel to be revisiting it after all this time?'" Winslet said. "But people ask me about 'Titanic' all the time, so it isn't like I'm revisiting it at all. It's part of my DNA."
"Titanic" was the highest-grossing film of all time, earning $1.8 billion at the box office and 11 Oscars, including Best Picture, until Cameron's "Avatar" sunk it in 2009 by making $2.77 billion.
"Titanic 3D" is headed back to theaters next month in time for the 100th anniversary of the ship's sinking.