"Avatar: The Way of Water" has beaten both "Top Gun: Maverick" which took 31 days in May to clear the box office milestone, and "Jurassic World Dominion" released in June which took over four months, according to Variety.
In 2021, "Spider-Man: No Way Home" took just 12 days. Only six movies in history have cleared $1 billion mark in their first two weeks of release.
Studios split ticket sales with theatres, and Cameron has said "The Way of Water" will need to make $2 billion just to break even. Disney has not disclosed the budget and marketing costs.
"The Way of Water" fell short of ticket sales forecasts as it first swept into theatres over the weekend of December 16, racking up roughly $435 million around the globe, distributor Walt Disney Co. said, including $134 million in the United States and Canada.
Pre-weekend predictions called for at least a $140 million domestic tally for Cameron's decade-in-the-making return to the story of the blue, Na'vi people on a moon called Pandora, and as much as $500 million worldwide.
Box office experts said it was too soon to judge whether the movie would recoup its massive costs.
The movie was released 13 years after the first instalment wowed audiences with pioneering 3D technology. The original "Avatar" remains the all-time box office champion with $2.9 billion in global ticket sales.
The sequel was delayed multiple times as Cameron and co-writers crafted a story to be told over four additional movies. A third "Avatar" instalment and part of a fourth already have been filmed.
In "The Way of Water," actors Sam Worthington and Zoe Saldana return as Jake Sully and Neytiri 10 years later, now parents of five children. Their peaceful life is interrupted when the Sky People, the Na'vi name for humans, return to go after Jake.
Reuters