The Mean Girls star addressed her recent troubles by joking about her summer "vacation" at Cliffside Malibu, the California rehab facility where she spent the last few months, insisting she is well-rested after her break, saying, "As you all know, for the past 90 days, I've been on a lovely court-ordered vacation in Malibu. On a real note, it was really great and wonderful."
She added, "I've been through a lot lately and I have a lot of people to thank... most notably the celebrities who kept the tabloid industry alive in my absence, like (New York politician) Anthony Weiner... (and) Kanye West...
"Kanye, I wanna thank you for acting like a baby and making a baby. On a side note, how come when Kanye acts like an idiot, he gets a gold record and when I act like an idiot I get a police record? I still haven't figured that out."
Then it was Justin Bieber's turn to be roasted by Lohan as she introduced one of Handler's regular guests, who was dressed like the Baby hitmaker and wheeling a mop bucket, just like the one the pop star urinated into in the kitchen of a New York City restaurant recently - while the actress was in rehab.
She added, "I wanna thank Justin Bieber... for peeing where you shouldn't, spitting where you shouldn't and wearing your pants where you shouldn't."
Lohan ended her opening monologue by also thanking Britain's new royal baby, Prince George of Cambridge, for filling the tabloid pages as Handler's pint-sized sidekick Chuy Bravo stepped out wearing a crown and a onesie emblazoned with the words 'Future King'.
She also had a special message to fans: "I'm back, I'm happy and healthy and I'm sorry paparazzi but if you wanna take pictures of someone who's really f**ked up, you're just gonna have to wait until Chelsea's back."
The show was taped last week (ends02Aug13), just two days after Lohan left the Cliffside rehab clinic.