As TMZ first reported, Susan was set to sing "Hallelujah" on the show tomorrow. But a rep for the show confirmed she won't be appearing this week.
No word yet on rescheduling.
A source tells us Susan missed a flight to L.A. today. She was supposed to tape her performance on the "DWTS" set this evening.
We're told host Tom Bergeron will address the issue on tonight's show.
Boyle was set to perform on "Britain's Got Talent" in September, until Lou Reed reportedly sent last-minute word she couldn't sing his 1970s hit "Perfect Day."