Lindsay Lohan will spend time with Charlie Sheen before checking into rehab.The troubled actress is to spend 90 days in an in-patient facility as part of a plea deal agreed this week relating to charges over a car accident last July and before she begins treatment - which must be before May 2 - she intends to make the most of her time by fitting in both work and pleasure.A source said: "Lindsay's pre-rehab plan? A week with Charlie Sheen in LA, then she wants to go to Brazil. I kid you not."Â During her time with her 'Scary Movie 5' co-star - who has repeatedly supported the actress, giving her $100,000 to pay a tax bill and offering to be her mentor - the 26-year-old actress will spend two days shooting a guest appearance on his TV show 'Anger Management'.Speaking of the role, her lawyer Mark Heller told the New York Post newspaper: "He's a therapist, and she'll play a patient who falls in love with him."Meanwhile, despite claims the 'Liz & Dick' star is romancing City of the Sun musician Avi Snow, Mark insisted there is nothing serious between the pair as she has "many boyfriends".He added: "Lindsay is a beautiful young woman who has many pursuers and many boyfriends."