Fifty Shades of Gray is a big hit on opening day

Fifty Shades Of Gray has kicked off the Valentine's Day weekend (13-15Feb15) with an expected box office high in America, while breaking opening day records around the world.

The erotic thriller scored Universal's biggest US opening day numbers thanks to a $8.6 million haul on Thursday night (12Feb15), and landed the second highest late-night showing for an R-rated film after The Hangover 2.

The film, starring Jamie Dornan and Dakota Johnson, is on track to gross over $50 million over the weekend, becoming the top Valentine's Day release of all time in the process.

The film version of E. L. James' raunchy bestselling novel is also expected to do well overseas, with some film industry experts predicting it could gross over $75 million .

It has already smashed opening day box office records for an R-rated film in the Philippines and Australia.