Angelina Jolie, Jennifer Lawrence and Lupita Nyong'o were among the celebrities that attended the BAFTAs 2018 in London on Sunday night.
The film awards season in the United States and elsewhere has been overshadowed by the allegations of sexual harassment and abuse leveled at scores of entertainment figures since women began coming forward to accuse Hollywood producer Harvey Weinstein past year.
Producer Graham Broadbent said the movie about a bereaved mother seeking justice is "the story of a woman taking on the establishment and status quo".
"We're having a great time", he gushed.
The best-actress race is an global contest, pitting American Frances McDormand as a bereaved mother in "Three Billboards" against Britain's Sally Hawkins for "The Shape Of Water", Irish actress Saoirse Ronan for "Lady Bird", US star Annette Bening for "Film Stars Don't Die In Liverpool" and Australia's Margot Robbie for "I, Tonya". Three Billboards also won for original screenplay (Martin McDonagh).
In addition, many in attendance wore badges citing the campaign against sexual harassment, while honourees and presenters, including Sam Rockwell and British actress Lily James expressed support for the movement.
In an open letter published Sunday before the awards, nearly 200 British and Irish stars backed a new fund to help women facing sexual harassment and abuse at work.
Other signatories to the letter included Kate Winslet, Keira Knightley - who donated £10,000 ($17,734) - and Bafta nominees Kristin Scott Thomas and Saoirse Ronan.
Announcing a fund to support women and men battling workplace abuse - modelled on the Time's Up movement in the USA - the stars said "with our collective power, we can galvanize others".
They posted on Twitter: "We just crashed the #EEBAFTAs red carpet to say #TimesUpTheresa: your DV bill is a unsafe distraction from what we really need, funding for refuges and specialist domestic violence services".
Video BAFTA nominees on what the 'Times Up' campaign means for them
The mother of Prince George, 4, and Princess Charlotte, 2, who is now pregnant in her third trimester, however, did wear a black tie around her dress above her glowing figure, in what may have been a subtle nod to fellow women.
More than 190 entertainers, academics and activists have added their signatures, giving their voice to the protests over sexual harassment which have been growing since allegations against American film producer Harvey Weinstein surfaced last October.
England's Old Vic Theatre has been rocked by allegations against former artistic director Kevin Spacey. London police are also investigating nine claims of sexual assault by Weinstein.
Now Britain's biggest stars are expected to follow suit as indicated by a letter that has been circulated around the British film and TV industry. "We need to examine the kind of womanhood our industry promotes and sells to the world".
The call to wear black put Kate in a delicate position, because the royal family is careful to avoid political statements.
Stars are starting to arrive for the British Academy Film Awards at London's Royal Albert Hall.
Gary Oldman took home the leading actor trophy for his Golden Globe-winning portrayal of British wartime Prime Minister Winston Churchill in Darkest Hour. Allison Janney was named best supporting actress for playing ice skater Tonya Harding's domineering mother in "I, Tonya".
The US-set film also won the best British film honours, qualifying on the basis of its creative team and the companies involved in producing it, many of whom are British.
The British trophies, known as BAFTAs, are considered a key indicator of likely success at Hollywood's Oscars in two weeks' time.