Madonna -- who turns 55 on Aug. 16 -- has defined trends and redefined her own personal style over the past four decades, making her a fashion icon. From her Marilyn Monroe-inspired, Old Hollywood waves to her punk, white blonde pixie to a Bettie Page bob, her Madgesty is constantly changing her look.

In honor of the big 5-5, we've looked back at what we think are Madonna's 10 most iconic hairstyles. She has had well more than 10, 20 or even 50 different looks. These are the ones where the hairs on her heard turned ours.

  • Princess Di Short 'Do

    For the cover of her 1986-released album 'True Blue,' Madge wore short, full, platinum layers that were inspired by Princes Diana, letting her sculpted brows and gorgeous features be the focus. She was no longer a boy toy, as was the case with 'Like a Virgin,' and her grown up haircut, complete with curling-iron created body, reflected that. This was the '80s, after all.

  • 'I Dream of Jeannie' High Pony

    Madge's 'I Dream of Jeannie' high pony, complete with a braid wrap, which she sported in the early '90s, is one of her most memorable for many reasons. What made it so appealing? Was it the flaxen, glossy color? The way the tightness pulled back her eyes and face, creating an exotic look? The sexy, goddess-like vibe? It was all of those things.

    Frank Micelotta, Hulton Archive, Getty Images
  • Marilyn Monroe Waves

    Madonna always modeled herself after screen icon Marilyn Monroe, but with an edge. It's a coif she revisited many times in her career, framing her face with her big, thick strands blown out and full of volume. It never ceased to be sexy.

  • Blunt Brown Bob With Bettie Page Bangs

    At the 2013 Met Gala, Madonna rocked a blunt, brown bob with Bettie Page bangs. It was her brunette take on Vogue editress Anna Wintour's iconic bob with beveled ends. Fabulous.

    Jamie McCarthy, Getty Images
  • Feathered Like Farrah Fawcett

    In her mom years, Madonna hasn't sacrificed her style. Here, she opted for a Farrah Fawcett-inspired, feathered 'do, complete with sideswept bangs. It merged a '70s cut with more modern swoopy bangs. The golden hue was also gorgeous on her. That Madge -- she's quite a coif queen.

    Evan Agostini, Getty Images
  • Messy Blond Chop

    The messy blond chop was a variation on the 'True Blue' cover look and it was separately iconic. Worn flat and tossed with her fingers and some mousse post-shower, it was tomboyish, but sexy all at once.

    Brenda Chase Hulton Archive, Getty Images
  • Blue Black With Bangs

    Madge rocked a Black Dahlia take on the Old Hollywood glam trend. She paired blue black locks with screen siren rolled bangs a la Joan Crawford. The deep, rich color drew attention to her baby blues. It was a recent dominatrix look, but like everything in life, she owned it.

  • Like a Virgin Bob

    Her textured, permed 'Like a Virgin' bob, full of messy, spiked layers was one of her best, thanks to its youthful, get up and go energy. Her mane was her crowning glory -- remember, she is a Leo, astrologically speaking.

  • Straight Layers

    Shaggy, shoulder-skimming layers, complete with purposefully peeking through roots, is also a style that Madge has adopted multiple times in her 40s and 50s. If it works, it works. The glossy hue and bangs prevent this from being soccer mom hair!

    Dimitrios Kambouris, Getty Images
  • Defined Blonde Waves

    Madge has been rocking twisty, golden waves for a while now. It's effortless, which is nice, since in addition to being a superstar and a style icon, she is also the mother of three. The center part allows the simple tendrils to fall around her face and show off those piercing eyes and that (still) stunning face.