While the 26-year-old actress and Charlie Sheen's former wife are both currently being treated at the Betty Ford Clinic, Lindsay is shunning Brooke, 35, because she thinks she is a ''drug addict''.
A source told RadarOnline: ''It's creeping Lindsay out that Brooke seeks her out nightly at the meetings in an attempt to strike up a friendship. Brooke is extremely eager to become besties with Lindsay while in rehab, and has told Lindsay how much they have in common.
''Brooke's publicist was Lohan's one-time rep, Steve Honig and Brooke has even played the Charlie Sheen card, pointing out that Charlie helped Lindsay pay off debts to the IRS, so they both have a close relationship to him.
''But Lindsay has said that Brooke is a drug addict, and wants nothing to do with her. Lindsay has told her treatment team to keep Brooke out of her group sessions.''
Meanwhile, Brooke is reportedly happy with all of the extra attention she has received since entering rehab and is hoping it will build her profile.
The source added: ''She isn't fazed by all of the negative publicity she has been getting since losing custody of Bob and Max to Denise Richards. In fact, she loves it, and thinks it will help her chances of landing a role as an actress on a television sitcom.''