"In hospital today having my 12th general anaesthetic in 8 months," he tweeted Aug. 15. "However, back to work on @SWardMusical tomorrow, even if a bit woozy. ALW"
The following day, he added, "Thank you for all the kind messages re my back op yesterday. Very happy to be working on @SWardMusical today and feeling much better. ALW."
As previously reported, the world premiere of his latest musical Stephen Ward will begin performances Dec. 3 at the West End's Aldwych Theatre, prior to an official opening Dec. 19.
The composer has experienced recent health issues and was unable to attend the 67th Annual Tony Awards, where his long-running musical The Phantom of the Opera was honored for its 25th anniversary.
A a statement via his website, AndrewLloydWebber.com, read, "I have been in constant pain since October 2012 following treatment for a problem with my right thigh. As a consequence I have undergone countless medical procedures and two major back operations."
Lloyd Webber won Original Score Tony Awards for his work on Evita, Cats and Sunset Boulevard. His other Broadway credits include The Woman in White, Bombay Dreams, Joseph and the Amazing Technicolor Dreamcoat, The Phantom of the Opera, Aspects of Love and Starlight Express, among others.