Back in December, Brooke Mueller entered rehab for the 19th time. So this new stint may be her 20th. 

According to RadarOnline, Brooke entered rehab at the Betty Ford clinic on Thursday, for the start of a 30-day stint; the site claims she specifically wanted to be in rehab with Lindsay Lohan, who is working on a 90-day rehab sentence.

Insiders told RadarOnline that the L.A. County Department of Children and Family Services didn’t want Brooke going to Betty Ford because of the Lindsay factor, but she disagreed. Apparently she wasn't legally forced to go to rehab, she got her way.

According to TMZ, Brooke and Lindsay are staying in the hospital wing at the Rancho Mirage center, and they've "exchanged pleasantries."

Brooke has twin sons with her ex-husband Charlie Sheen. The boys were recently removed from Brooke’s home because authorities suspected she was using drugs again. The boys are now staying with Charlie's other ex-wife, Denise Richards.

Sources: RadarOnlineTMZ