The actress was joined by Billy Zane and director James Cameron at the Royal Albert Hall event and she was all smiles at finally attending a big premiere.
Winslet missed out on the Los Angeles launch of the film in 1997 to mourn the death of her ex-boyfriend Stephen Tredre, who lost his battle with cancer.
She was subsequently forced to skip the U.K. premiere because she was in hospital after contracting dysentery while filming Hideous Kinky in Morocco - but 15 years on, she has finally hit the red carpet for a Titanic launch.
Producer Jon Landau told reporters, "I'm so excited that we're here with Kate Winslet because she wasn't here the first time we premiered the movie. So that fact that she's here to support the film is very exciting."
Cameron flew into London for the premiere from Guam, where earlier this week (begs26Mar12) he performed the deepest ever solo submarine dive.