She's headed to rehab, Page Six reports, using a cover her ex Lindsay Lohan would appreciate: Exhaustion, which Lohan used to claim crippled her on movie sets (before she was arrested for cocaine possession).
A rep for Semel tells us, "Courtenay has indeed checked into rehab . . . She's emotionally, physically and mentally exhausted.
It's hard to tell what left Semel more tired out: Allegedly punching that security guard in Las Vegas, purportedly setting girlfriend and fellow heiress Casey Johnson's hair on fire (a charge Semel denies) or working on that reality show.
Actually, none of the above: Our money's on "trying to live for a month without access to daddy's money." Talk about exhausting.