Country singer Larry Gatlin, 36, says he has entered CareUnit, a rehabilitation center in Orange, Calif., "as a voluntary patient for the treatment of alcohol and drug addiction" . . .

Ms. Magazine honored its 12 Women of the Year at a champagne breakfast Thursday at New York's Studio 54. Among the honorees were Geraldine Ferraro, singer Cyndi Lauper, and National Education Association president Mary Hatwood Futrell. Also joining the ceremony were Ms. Magazine editor Gloria Steinem and Time Magazine Man of the Year and baseball commissioner Peter Ueberroth . . .

Gary Coleman, star of TV's "Diff'rent Strokes," returned to work Thursday at Universal Studios after a second successful kidney transplant . . .

Also planning to return to day-to-day activities is country singer Barbara Mandrell, 36, who sustained several fractures and a severe concussion in a Sept. 11 car accident near Nashville that killed the teen-age driver of the other car. Mandrell said she would be making public service testimonials about the importance of wearing safety belts . . .

Rick Allen, 21, drummer for the British rock band Def Leppard, had his left arm amputated yesterday in Sheffield, England. The arm was sewn into place after being severed four days ago in a car crash. "Because of the extent of the infection, there was no alternative but to amputate the arm," said a spokeswoman for his recording company . . .

Comedian Jerry Lewis has filed a copyright infringement lawsuit against Paramount Pictures Corp. for $10 million. The suit claims the studio illegally sold videocassettes of Lewis' 1963 film "The Nutty Professor." Paramount distributed the film when it first came out . . .