The 53-year-old actress - who is married to TV producer David E. Kelly - has admitted it wasn't until she portrayed "sexually appealing" Susie Diamond in 'The Fabulous Baker Boys' when she was 31 that she decided to stop looking like a "bag lady".
She said: "I struggled with my own image as a sexual person. That ended with a film, 'The Fabulous Baker Boys' in 1989, by which time I was 31.
"Even two years before that, I would not have been able to play the part of the sexually appealing Susie Diamond. She was dynamic and unapologetic and I was able to put on those clothes and play the part. I think, because of the way I looked, I had stayed away from buying anything sexy or overtly sexual.
"It was a turning point for me, because I could understand why men would find her sexy. I wish I'd been more like her. Before that, I would walk around looking like a bag lady!"
However, the 'Dark Shadows' star explained becoming a mother to daughter Claudia Rose, 18, and son John Henry, 17, was the biggest "turning point" of her life because it has been the most rewarding thing she has done with her life.
Michelle added in an interview with The Sun newspaper: "The biggest turning point in my life was becoming a mother. If you had told me when I was 18 that I could survive on three hours' sleep a night, I'd have never believed it. You just cope.
"I would not choose a show-business career for my children. I would say, 'Be a doctor, or something else.' The value of a good education has never left me."