In fading health for several years, Hepburn died at her home in Old Saybrook, Connecticut on Sunday afternoon.

Tributes immediately poured in and Broadway announced that the lights would be dimmed on the US theatre capital on Tuesday night.

Hepburn's career spanned six decades during which she became one of the most-acclaimed actresses of all time. She was outspoken and her longstanding affair with Spencer Tracy brought drama and controversy to her life.

They made nine films together and remained a couple until Tracy's death in 1967.

But no woman has matched the four Academy Awards she won and the American Film Institute counted her among the greatest film icons, alongside Humphrey Bogart, Cary Grant and Bette Davis.

She was nominated 12 times and won Oscars for "Morning Glory" (1933), "Guess Who's Coming to Dinner" (1967), "The Lion in Winter" (1968) and "On Golden Pond" (1981).

As the straitlaced missionary's sister opposite drunken river boat captain Bogart in "The African Queen" (1952), or the society girl in "The Philadelphia Story" with Cary Grant (1940), Hepburn combined regal attitudes with just enough humanity to endear her to audiences.

The first award came only a year after making her first film, "A Bill of Divorcement" (1932). She kept making a huge variety of movies until retiring in 1994 when she appeared in "Love Affair", "One Christmas" and "This Can't Be Love."

She also starred with Cary Grant, John Wayne and James Stewart.

Hepburn was born in Hartford, Connecticut on May 12, 1907, the second of six children of a wealthy surgeon and a suffragette activist, who shaped Hepburn's character and career.

"I've had a pretty remarkable life, but compared to my mother and father, I'm dull," she once said.

"The single most important thing anyone needs to know about me is that I am totally, completely the product of two damn fascinating individuals who happened to be my parents."

She scored her first major success on Broadway in "The Warrior's Husband" (1932), not long after graduating in 1928 from Bryn Mawr college in Pennsylvania with a degree in drama.

A short-lived marriage to a broker Ludlow Smith ended in 1934.

She went on to have a series of relationships, including a three-year affair with reclusive millionaire Howard Hughes.

"In my relationships, I know that I have qualities that are offensive to people -- especially men. I'm loud and talkative and I get on to subjects that irritate."

Spencer Tracy was the love of her life however even though it was an often stormy 25-year-long relationship.