The main accessory for the men seemed to be tidily cut beard – with Leonardo DiCaprio and Michael Fassbender leading the way.
Irish actor Fassbender turned up with a mystery blonde and made a relatively quick entrance, while ‘Wolf of Wall Street’ star DiCaprio spent almost an hour signing autographs on the red carpet.
Brad Pitt and Angelina Jolie walked into the venue hand in hand, waving to onlookers as they arrived.
Stars also wowing in the style stakes tonight are Gillian Anderson, Fearne Cotton, Edit Boman, and Rebecca Wang.
Leonardo DiCaprio was the crowd's main interest for the night - as they chanted his name in anticipation of his arrival.
Director Steve McQueen is tipped to win the best film prize for his harrowing drama "12 Years a Slave".
The British Academy Film Awards (BAFTAs), handed out two weeks before the Academy Awards, are widely seen as indicators of Oscar success - the winning film at London has taken the top prize in Hollywood for the past two years.
Space thriller "Gravity", starring Sandra Bullock and George Clooney, led the field with 11 BAFTA nominations, just ahead of "12 Years a Slave" and "American Hustle", each running in 10 categories.
Bullock was expected to join Leonardo DiCaprio, Oprah Winfrey and Tom Hanks on the red carpet at the Royal Opera House, alongside British names including Judi Dench and Emma Thompson.
Britain's Prince William will present an Academy Fellowship for outstanding contribution to film to British actress Helen Mirren, who won an Oscar for playing his grandmother Queen Elizabeth in the 2006 film "The Queen".
Mirren said it was extraordinary to receive a fellowship that has been given to the likes of Alfred Hitchcock, Laurence Olivier, Steven Spielberg and Elizabeth Taylor.
"I've always thought of myself, believed myself, to be slightly on the outside of the mainstream as an actress ... I've done OK but I'm never going to be like one of those people," Mirren, 68, told reporters ahead of the award ceremony.
Bookies expect "12 Years a Slave", based on a true story about a man kidnapped and sold into slavery, to be the big winner of the night.
The film that has already won a slew of awards is tipped to take four of the major BAFTA categories including best film, best director, best actor for Briton Chiwetel Ejiofor and best supporting actress for Lupita Nyong'o.
"The odds suggest that "12 Years A Slave" will sweep the boards," bookmaker William Hill's spokesman Rupert Adams said.
A major rival is 1970s con-men caper "American Hustle", starring Bradley Cooper, Christian Bale and Amy Adams who are also expected to attend.
Other films in the running are Somali pirate thriller "Captain Phillips" and British drama "Philomena", starring Judi Dench as an Irish woman trying to find the son she gave up for adoption.
Vying for the best actor prize alongside Ejiofor are Bale in "American Hustle", Bruce Dern in "Nebraska", DiCaprio in Martin Scorsese's tale of American greed "The Wolf of Wall Street" and Tom Hanks in "Captain Phillips".
British veteran Dench, 79, who garnered a record 15th BAFTA nomination, is one of five women competing for best actress. The bookies' favourite is Cate Blanchett playing a riches-to-rags socialite in Woody Allen's tragic comedy "Blue Jasmine".
Also in the running are Adams from "American Hustle", Emma Thompson in "Saving Mr. Banks" and Bullock in "Gravity".
The BAFTA ceremony will be televised from 2100 GMT.