The 42-year-old chose an elegant black dress with three-quarter length sleeves by French designer Isabel Marant, showing off her enviable figure.
Cameron Diaz in an Isabel Marant dress
Cameron added some animal-print Givenchy low-heeled sandals to complement her outfit, finishing off the look with one of Chanel's iconic black quilted handbags.
The American beauty wore her hair in a sleek low ponytail and kept her makeup to a bare minimum, opting for some dark nail polish for a more dressed-up beauty style.
Cameron was not the only actress to turn heads on the red carpet in a striking outfit.
Gwyneth Paltrow wowed at the luncheon in a white dress with mesh cut-out detail by Roland Mouret, showing off her toned legs.
The 42-year-old opted for some black gladiator stilettos with snakeskin detail, and wore her hair down in a poker straight style. Gwyneth also sported a pale pink lipstick teamed with barely-there makeup for a fresh-faced look.
Gwyneth Paltrow in a Roland Mouret dress
Gwyneth has been repeatedly showing off her style credentials since she and husband Chris Martin announced their 'conscious uncoupling' on her lifestyle website Goop.
The Iron Man 3 actress recently had fans coveting a black crop top and mid-length lace skirt combo she wore as she headed to the theatre for the opening night of her mother Blythe Danner’s play The Country House.
Gwyneth was also spotted celebrating her 42nd birthday by having cocktails at home with some of her closest friends. Well-wishers included Kate Hudson and fiancé Matt Bellamy, Tobey Maguire and his wife Jennifer Meyer Maguire, Nicole Richie and Maya Rudolph.