Blethyn 's breakthrough came with Mike Leigh 's 1996 drama '' Secrets & Lies '' . Starring alongside Marianne Jean-Baptiste , she portrayed a lower-class box factory worker , who after years once again comes in contact with her illegitimate grown-up black daughter , whom she gave up for adoption thirty years earlier . For her improvised performance , Blethyn was praised with a variety of awards , including the Best Actress Award at the 1996 Cannes Film Festival , the British Academy Award , a BAFTA Award , a Golden Globe and an Academy Award nomination for Best Actress . Upon its success , Blethyn later stated : " I knew it was a great film , but I did n't expect it to get the attention it did because none of his other films had and I thought they were just as good . Of course , I did n't know what it was about until I saw it in the cinema because of the way that he works — but I knew it was good . That it reached a wider audience surprised me . " Besides critical acclaim '' Secrets & Lies '' also became a financial success ; budgeted at an estimated $ 4.5 million , the film grossed an unexpected $ 13.5 million in its limited theatrical run in North America
1996 Cannes Film Festival
1996 Cannes Film Festival
Brenda Blethyn