LONDON (AP) — James Cameron’s sci-fi extravaganza Avatar was getting its public premiere in London Thursday, and the movie industry is watching intently to see whether it will match the success of the director’s blockbuster, Titanic.

Stars Sigourney Weaver, Sam Worthington and Zoe Saldana were expected to join the crowds in London’s Leicester Square before Thursday’s gala screening.

The 3-D epic about humans taking extraterrestrial form as they explore a distant world is reportedly one of the most expensive movies ever made, with a price tag well in excess of the $200 million spent to make Titanic. It uses cutting-edge digital technology to create dizzying special effects.

Cameron conceived the story for Avatar in 1995 then waited a decade for technology to catch up so he could film it. The film mixes live action and computer animation to create an eye-poppingly vivid alien world.

The industry is watching closely to see how audiences respond to Cameron’s first narrative film since 1997’s Titanic, which won 11 Academy Awards and has taken $1.8 billion worldwide at the box office.

Avatar opens around the world next week.