Showcasing her dancing abilities, Hepburn starred opposite Fred Astaire in the musical Funny Face (1957). This film featured Hepburn undergoing another transformation. This time, she played a beatnik bookstore clerk who gets discovered by a fashion photographer played by Astaire. Lured by a free trip to Paris, the clerk becomes a beautiful model. Hepburn’s clothes for the film were designed by Hubert de Givenchy, one of her close friends.

Stepping away from lighthearted fare, Hepburn co-starred in the film adaptation of Leo Tolstoy's War and Peace with her husband, Mel Ferrer, and Henry Fonda in 1956. Three years later, she played Sister Luke in The Nun's Story (1959), which earned her an Academy Award nomination. The film focused on her character's struggle to succeed as a nun. A review in Variety said "Audrey Hepburn has her most demanding film role, and she gives her finest performance." Following that stellar performance, she went on to star in the John Huston-directed western The Unforgiven (1960) with Burt Lancaster. That same year, her first child, a son named Sean, was born.

Returning to her glamorous roots, Hepburn set new fashion standards as Holly Golightly in Breakfast at Tiffany's (1961), which was based on a novella by Truman Capote. She played a seemingly lighthearted, but ultimately troubled New York City party girl who gets involved with a struggling writer played by George Peppard. Hepburn received her fourth Academy Award nomination for her work on the film.

For the rest of the 1960s, Hepburn took on a variety of roles. She starred with Cary Grant in the romantic thriller Charade (1963). Playing the lead in the film version of the popular musical My Fair Lady (1964), she went through one of the most famous metamorphoses of all time. As Eliza Doolittle, she played an English flower girl who becomes a high society lady. Taking on more dramatic fare, she starred a blind woman in the suspenseful tale Wait Until Dark (1967) opposite Alan Arkin. Her character used her wits to overcome the criminals that were harassing her. This film brought her a fifth Academy Award nomination. That same year, Hepburn and her husband separated and later divorced. She married Italian psychiatrist Andrea Dotti in 1969, and the couple had a son, Luca, in 1970.

In the 1970s and 1980s, Hepburn worked sporadically. She starred opposite Sean Connery in Robin and Marian (1976), a look at the central figures of the Robin Hood saga in their later years. In 1979, Hepburn co-starred with Ben Gazzara in the crime thriller Bloodline. Hepburn and Gazzara teamed up again for the 1981 comedy They All Laughed, directed by Peter Bogdanovich. Her last screen role was in Always (1989) directed by Steven Spielberg.

In her later years, acting took a back seat to her work on behalf of children. She became a goodwill ambassador for UNICEF in the late 1980s. Traveling the world, Hepburn tried to raise awareness about children in need. She understood too well what it was like to go hungry from her days in The Netherlands during the German Occupation. Making more than 50 trips, Hepburn visited UNICEF projects in Asia, Africa, and Central and South America. She won a special Academy Award for her humanitarian work in 1993, but she did not live long enough to receive it. Hepburn died on January 20, 1993, at her home in Tolochenaz, Switzerland after a battle with colon cancer.

 Source = http://www.biography.com