Leading British choreographer Dame Gillian Lynne has died aged 92.
She passed away on Sunday evening at the Princess Grace Hospital in central London, her actor husband Peter Land said on Twitter.
Dame Gillian began her career as a ballet dancer but achieved her greatest success in the theatre world, devising the dances for Lord Lloyd-Webber's Cats and Phantom of the Opera.
Theatres in London's West End will dim their lights on Monday in her memory.
Dame Gillian worked on more than 60 shows in the West End and Broadway.
Lord Lloyd-Webber paid tribute to her on Twitter, writing: "Farewell dearest Gillie, three generations of the British musical owe so much to you."
Last month Dame Gillian attended a renaming ceremony hosted by Lord Lloyd-Webber and producer Cameron Mackintosh, as the original London home of Cats was renamed in her honour.
The New London Theatre, now known as the Gillian Lynne Theatre, has become the first West End venue named after a non-royal woman.
Dame Gillian, who was born in Bromley, south-east London, started her career at the age of 16 performing classical roles with the Sadler's Wells Ballet, moving on to stage musicals and television in the 1950s.
She went on to work as a choreographer for the Northern Ballet and the Bolshoi.
In 1981 Dame Gillian took on Cats which ran for almost 9,000 performances in London, and five years later Phantom, a major international success and seen by many as her greatest achievement as a choreographer.
Her other credits include Lloyd-Webber's Aspects of Love, the stage version of Chitty Chitty Bang Bang and Barbra Streisand's film Yentl.
She won two Olivier Awards during her career, as well as a Golden Rose of Montreux Award for her work on TV's Muppet Show, and a Bafta for the BBC dance drama A Simple Man.
Her damehood in 2014 was for services to dance and musical theatre.
Elaine Paige, who played the lead in the original production of Cats, paid tribute her "dear friend and teacher".
The Heaviside Layer is thought to be a reference to heaven.
There was also praise from actress Dame Joan Collins, who described Dame Gillian as "brilliantly talented".