Actress Leighton Meester. (DANNY MOLOSHOK/REUTERS)

In the suit, obtained by E! News and TMZ, the actress alleges her mother, Constance Meester, used the $7,500 a month she sent home for her ill brother, Lex, for cosmetic procedures, including Botox injections, and hair extensions instead.

Meester’s attorney said she’s “endured a difficult relationship with her mother,” according to E!. Her attorney also claims Constance told her daughter they had an oral contract for Leighton to send $10,000 a month and threatened to sue for $3 million if she didn’t comply.

“Leighton never agreed to pay Constance any amount of money, let alone financially support Constance for the rest of her life,” the suit says.

Constance Meester has been in legal trouble before. She gave birth to Leighton in federal prison while serving time for smuggling drugs, according to the actress.