The South African-born royal turned heads with her stunning choice of outfit — a white strapless jumpsuit with flared legs, held in at the waist with a matching belt.
Charlene was attending the screening of To Catch A Thief, the 1955 thriller which starred her legendary late mother-in-law Grace Kelly, and was directed by Alfred Hitchcock.
The radiant princess happily posed for pictures with the organiser of the event, Ralph Lauren, his wife Ricky and the couple's son Andrew.
Charlene looked to be enjoying the New York affair, which was held at the Museum Of Modern Art, as she stepped inside for more pictures with Ralph against the lavish backdrop.
Other celebrities who attended the high-profile event included actor Chris Noth, actress Toni Collette and models Coco Rocha and Chanel Iman.
Charlene's appearance comes days after her visit to a new exhibition in Pennsylvania with her husband Prince Albert. The display gives an insight into the life of Prince Albert's mother, Princess Grace.
"Most of the world knows my mother first as a Hollywood film actress, then as the princess of Monaco," said the prince in a video at the event.
"She was indeed a beautiful and talented woman and a fashion icon but that is just the surface of her life.
"Those of us who were fortunate enough to know my mother, her family and friends, knew her to be a genuine, warm and loving woman. A woman who always put her family first.
"I hope that through experiencing this exhibition, you will be able to get a glimpse of the real Grace Kelly, the woman beyond the icon, my mother."