The 26-year-old "Mean Girls" and "Freaky Friday" actress said during an interview with David Letterman -- her first television chat anywhere since November -- she will begin her court-ordered treatment for drug and alcohol addiction May 2.
"How many times have you been in rehab?" Letterman asked Lohan, to which the actress admitted, "Several."
"And how will this time be different?" Letterman pressed. "What are they rehabbing, first of all? What is on their list? What are they going to work on when you walk through the door?"
"I think, to be honest, I'm the happiest when I'm working and the healthiest, and I think this an opportunity for me to, you know, focus on what I love in life. And I don't think it's a bad thing. I think it's a blessing... and not a curse," she said.
"It's perhaps a life saver, a career saver," Letterman agreed as the audience applauded.
"Yeah," Lohan said.
Tuesday marked Lohan's fifth visit to the "Late Show." Her last appearance was May 9, 2007. Currently, the actress is promoting her upcoming guest star role in the comedy series "Anger Management" and in the new film "Scary Movie 5," which opens Friday. Both projects star Charlie Sheen, an actor who has battled addictions to drugs and alcohol, as well.
Lohan was ordered to undergo 90 days of in-patient treatment for her substance-abuse issues for probation violations related to her past drunken driving and necklace theft court cases.