Drew Barrymore's half-sister Jessica Barrymore was found dead inside her car in National City, California, on Tuesday, according to local news station KGTV. She was 47.
A woman whose car was was blocked in by Barrymore reportedly found her unconscious in the car at 6 a.m. with the seat reclined.
Barrymore would have turned 48 on Thursday. She and actress Drew are both daughters of the late actor John Barrymore, who died at age 72 in 2004 after battling drug and alcohol addiction for much of his life. Jessica's cause of death is still unknown.