Olivia de Havilland was a big player in Hollywood's golden era. The Gone With The Wind actress turns 100 this week, and told People she plans to celebrate the big day with "dinner and drinks with dear, dear friends."In the 1940s and '50s, de Havilland was a leading star of both the studio system and the gossip columns. She rose to fame in movies with Errol Flynn, played Melanie Hamilton Wilkes in Gone With The Wind, and dated Howard Hughes, Jimmy Stewart, and John Huston. In May, Vanity Fair crowned her the "last surviving female superstar of Hollywood’s Golden Age."As a centenarian, de Havilland's spark has only increased. She told People about her unlikely pen pal: Jared Leto."I was more than surprised to hear from Jared Leto," she said. "I was enchanted! He came to my house to thank me for the de Havilland Decision, which he and his band, 30 Seconds to Mars, had utilized victoriously in a similar contractual dispute."The de Havilland Decision was a landmark 1944 case that freed Hollywood talent from studio system serfdom. De Havilland told People that Leto's attorneys used the case's precedent in a contractual dispute.Outside of Old Hollywood's glitz and glamour, de Havilland was infamous for shading her sister (and bitter rival) Joan Fontaine at every opportunity. The two women remain the only pair of sisters to both win Academy Awards for Best Actress. In honor of her birthday, the actress revealed to CBS that she calls her sister (who died in 2013) "Dragon Lady.""If Dragon Lady were alive today (for my birthday)," de Havilland said, "out of self-protection, I would maintain my silence!"