The baby was born at 1:30 a.m. and weighed in at 7 lbs. 12 oz. Fisher, 38, gave birth at home in Los Angeles.
"The baby is gorgeous and healthy," Fisher's rep, Brit Reese, tells PEOPLE. "Everybody is resting comfortably."
True joins big sister Skylar, 4, and stepbrothers Cameron Duddy, 20, and Colin Duddy, 18. Fisher and Duddy, 44, a cinematographer, wed in 1997 on the soundstage of the Hollywood studio where they met.
"I painted, 'Vote 4 Lisa and Louie,'" pal Lisa Rinna, plugging her appearance on Dancing with the Stars, said at the time. "But I painted another tile that said 'True Love,’ so I think I redeemed myself."
Other guests at the shower included Camryn Manheim, Kristin Chenoweth and Debbie Reynolds (the ex-wife of Fisher's father, Eddie Fisher), who brought a cake made from baby booties, safety pins and ribbons.