Andrew Lloyd Webber is preparing to celebrate his Phantom of the Opera becoming the longest running musical on Broadway with 7,468 performances.
Phantom of the Opera opened on Broadway in 1988
On Monday, Phantom will take over the record set by Cats, another of Lord Lloyd-Webber's musicals.
He told BBC Radio 4's Front Row he knew he had a successful show on his hands before it even opened.
"It was clear it was going to be a hit but nobody knew just how big it was going to be," he said.
"There was so much interest in America before its opening there was a huge advance. It was $18m which would be more like $30m (£17m) today."
Lloyd Webber wrote Phantom of the Opera
He added that his first-night nerves were more tied to the fact his then-wife Sarah Brightman was in the starring role in her Broadway debut.
The composer also spoke about the future of the stage, saying he saw it being more in tune with the Little Britain live show rather than the traditional musical.
Praising it as a fantastic production, Lord Lloyd-Webber said: "Those guys have got the rhythm of musical theatre.
"They are the sort of audience we want to get. My kids are more interested in going to see Little Britain than they are (Broadway's) Spamalot."
He admitted that he sometimes visits theatres where Phantom of the Opera is being staged, but finds it difficult to go incognito.
Lord Lloyd-Webber said he was looking forward to celebrating the longevity of Phantom but was disappointed Brightman would not be there as she has recording commitments elsewhere.