Then came news in August that the 48-year-old actress had been arrested at Los Angeles International Airport, after police found a "small amount" of drugs and a hypodermic needle in her possession. Shortly after, TMZ.com reported that she was entering rehab -- for the 10th time.
Phillips just can't seem to escape either her genes or her past.
"I grew up in mansions, but everything was dirty and broken," she told USA Weekend magazine in 1999. "Very little was going on inside except sex, drugs and rock 'n' roll."
Her father, John Philips, founder of '60s folk-rock group The Mamas and Papas, was widely known for his heavy narcotic use. On "The E! True Hollywood Story," he admitted that he shot cocaine and heroin into his body "almost every 15 minutes for two years." Even after receiving a liver transplant in 1992, he was photographed drinking. He died in 2001 at age 65.
"Why did I survive?" Phillips asked USA Weekend. "Maybe it's to say to others, 'This happened to me. It could happen to you.' I don't mind being a poster girl."
Charlie and Martin Sheen
Martin Sheen has talked publicly about suffering from alcoholism. So when he saw his son Charlie headed down the road to addiction, he quickly sprang into action.
He recently told the AARP magazine that he turned to Alcoholics Anonymous for help. "I only got involved with AA when I was trying desperately to find a way to help Charlie, because I didn't have any skills," he said.
Charlie, who had developed a bad-boy reputation for his partying and drug use, was hospitalized for a drug overdose in 1998 when he tried injecting cocaine.
"The only way I got to Charlie, frankly, was because he'd skipped out of the hospital," Sheen told the magazine. "I had to pay the bill."
"He'd consumed an illegal substance; he was on probation," Sheen explained. "This was a criminal matter. And so that was the wedge; that was the leverage I had. That is what I took to the court; that's what I took to the sheriff. It was the only way I got him."
After a warrant was issued for his arrest, Charlie signed up for rehab.
Daniel and Stephen Baldwin
In the famous Baldwin family, with brothers Alec, Daniel, Billy and Stephen, the glare of Hollywood is a fact of life. And so, it seems, for two of the brothers, is addiction.
Since taking his first hit of cocaine in 1989, actor Daniel Baldwin has been marred by failed attempts at sobriety.
His drug problem started making headlines after a very public overdose in New York City's historic Plaza Hotel in 1998, and he had another very public relapse in 2005 on VH1's "Celebrity Fit Club," on which he erupted during filming. Daniel admitted to becoming addicted to pain medication and eventually left the show.
ABC's "Primetime" followed Daniel through rehab last year, when he admitted that he will always be an addict: "The addict will always be there, forever. I am an addict. That's just the way it is."
His younger brother Stephen, also an actor, has written about his struggles with drug addiction in his book, "The Unusual Suspect." Going to rehab introduced Stephen to Christianity and since then, he has become a born-again Christian.
"It's real. It's changed my life. It's transformed my heart. I'm not who I was," Stephen said.
ABC News' Lauren Cox and Rena Furuya provided additional reporting.