Diddy’s (54) ex-girlfriend Cassie (real name Cassandra Ventura), 37, claims she was trapped in a cycle of abuse and violence for ten years.
Diddy rejects this, accusing the singer of an extortion attempt.
His lawyer said the allegations were “offensive and cruel”.
Cassie claims the rap producer raped and beat her over a period of more than 10 years, starting when she was 19 and he was 37.
“After years of silence and darkness, I am finally ready to tell my story,” Cassie said in a statement.
The lawsuit includes several detailed descriptions of the abuse, which she says took place after she met the rapper in 2005.
The complaint alleges that Mr. Combs partnered with Cassie at Bad Boy Records and “seduced the vulnerable Ms. Ventura to drugs and alcohol, causing her to fall into dangerous addictions that controlled her life.”
The lawsuit describes Diddy as “a serial domestic abuser who regularly punched and kicked Ms. Ventura, leaving bruises under her eyes, abrasions and blood.”
The singer also claims that after she tried to end their relationship in 2018, Combs forced his way into her house and raped her.
Their professional relationship lasted until 2019.
In her statement, Ventura said she was ready to “speak up for myself and for other women who are experiencing abuse in their relationships.”
Mr Combs’ lawyer said Ms Ventura had demanded $30m (€27.7m) in damages, “threatening to write a damning book about their relationship”.
Cassie released several hits in the early 2000s, including songs featuring Diddy.
Her most famous songs include “Me & U” and “Long Way to Go”.