MACKENZIE PHILLIPS FACES HER DEMONS - ON FILM, THIS TIME.

Byline: Marilyn Beck & Stacy Jenel Smith

Mackenzie Phillips, who devastated her career and her life with the raging cocaine habit that caused her to be written out of CBS' ``One Day at a Time'' in 1980, has put her drug demons behind her.

Again.

The actress has wrapped work on what she admits was a frightening assignment - playing a hooker/heroin addict in the big-screen ``Mama Why?''

``I never wanted to look at the paraphernalia that goes along with drug use again, let alone handle it and pretend to be using it,'' acknowledges Mackenzie, who admits she had grave reservations about accepting the assignment. ``It was scary because the whole mind-set of addiction is so destructive - and I had to put myself back in the problem for the role.''

Based on a true story, ``Mama Why?'' has Phillips' character becoming friendly with a cop who's attending film school at night. ``He begins documenting her life on video, and through their relationship she finds recovery. But it's really the story of how her little boy survives her addiction,'' adds Phillips, who also has a 9-year-old son. ``Sort of mirroring my life in a way.''

Clean for more than five years now, Phillips has been fighting hard to make the climb back in the show-business world. After what she claims was a blackballing by the industry that lasted more than a decade, she's had guest roles on ``Melrose Place'' and ``NYPD Blue,'' has been touring with ``Grease'' since February - and beginning Tuesday joins the musical's Broadway production.

From the inside looking out: Lesley-Anne Down, in her second week of production on the big-screen ``Saving Grace'' being directed by her husband, Don Fauntleroy, reveals the film would also have featured her 14-year-old stepdaughter Julianna - if the teen had had her way.

Down vetoed the idea fast.

``There will be no acting for her until she's 18,'' says the English actress, who'll be seen as hostess of AMC's ``British Invasion'' of films on Sept. 26. ``Oh, Julianna and I had a row over that. I was the bitch cow from hell. She said, `You can't tell me what to do,' and I said, `I'm telling you how you're going to live until you're of age.' ''

Down feels strongly that ``most people who start out too early in my business don't last until they're 30. Many are either washed up - or dead from drugs. I started acting when I was 12 - and I know the mistakes I made.''

Drug usage was one of those mistakes - and even became a point in her divorce from director William Friedkin in the mid-'80s - when he sued for custody of their young son, Jack. Today Jack is 13 and is ``like a ping-pong ball, going back and forth between his father's house and mine.''

Ohh, please: That's a knee-slapper - Geraldo Rivera is calling for an end to misrepresentation and exploitation on TV talk shows. That would be like John Gotti calling for an end to organized crime.

Batting 1.000: Fran Drescher's future on the big screen won't depend on how well her first movie starring vehicle, ``Beautician and the Beast,'' fares at the box office when it's released by Paramount next year. The star of ``The Nanny'' not only has a second headlining movie project lined up (TriStar's ``Schlepped Away''), she's looking at several other A-list feature projects to do after that. Prospects include ``The Ump,'' a saga of the fictional first femme baseball umpire, from the folks who bring us ``Home Improvement.''

MEMO: The Celebrities column appears Monday through Friday.