Lindsay Lohan is going into rehab next month, but first she had to face David Letterman.

In an appearance taped for Tuesday's "Late Show," Lohan was pressed by Letterman about her upcoming rehab stint. She faces a 90-day stay as part of a plea deal in a misdemeanor traffic accident case.

Letterman tried to draw Lohan out, asking how many times she'd been in rehab, how this time would differ, and what she's being treated for.

Lohan looked uncomfortable and said she didn't expect Letterman's line of questioning.

But she said that she wants to be healthy and focus on what she loves — her work. She added that she looks at rehab as "a blessing and not a curse."

CBS released a partial clip of the interview before it aired.