Her music is the background soundtrack for Harry Potter and the Cursed Child, a play which looks at what life is like for Harry and his friends 19 years after the last book.
But Imogen says even though people want a record, she's not made one yet.
She was speaking at the official opening in London's West End.
"I think they want it to happen," she said.
"It's not like a musical, it's more like a film score. So it doesn't really have a Harry Potter moment."
