Actress Liz Sheridan, famed for playing Jerry Seinfeld’s sitcom mom and being James Dean’s 1950s lover, has died at the age of 93. The star passed away from natural causes around 2:30 a.m. on Friday, TMZ reports. PING She is the only “Seinfeld” star — apart from the four main leads — to be featured in all nine seasons of the hit sitcom.