Police went to the Hollywood Hills home of the 23-year-old’s ex-girlfriend, Hunter Daily Salomon, before dawn on Saturday.
According to reports Conrad – who is the heir to the Hilton Hotel empire – was found in a Bentley owned by the father of his former girlfriend.
Hunter’s father is Rick Salomon, who once dated Paris Hilton and appeared in an infamous sex tape that propelled the heiress into the spotlight.
Salomon has also been twice married and divorced to former Baywatch star-turned campaigner Pamela Anderson.
Bail has been set at $60,000.