Marilyn Monroe is known as one of the greatest Hollywood beauties who ever lived but the screen legend had one secret: She had plastic surgery.

X-rays and medical records of the late actress, which are to going on the auction block next month, appear to show that Monroe had facial plastic surgery during the 1950s.

The New York Post reports that the "Seven Year Itch" star had a cartilage chin implant, which according to notes written by her plastic surgeon Michael Gurdin, were done for cosmetic reasons because her chin had started to dissolve.

In addition to the chin implant, Monroe also had tip rhinoplasty on her nose, according to the auction website.

The memorabilia, which is set to go up for auction on Nov. 9, is expected to fetch anywhere from $15,000 to $30,00 and were put up for sale by a friend of Dr. Gurdin who has decided to stay anonymous.

The revelations that Monroe, who was famous for her bodacious figure and president-catching looks, comes as a surprise partly because the "Some Like It Hot" star visited doctors under the alias "Miss Joan Newman" to throw off anyone who could have told a tabloid.

"Nobody really thought about Marilyn Monroe having plastic surgery. It was always speculation - did she or didn't she?" said Martin Nolan, executive director of Julien's Auctions, who is handling the Monroe documents. "They thought she was such a natural beauty, they didn't want to believe."

It seems that plastic surgery is more prevalent than ever today, with stars such as Pamela Anderson, Jennifer Grey, Sharon Osbourne and Joan Rivers admitting to going under the knife.

Marilyn was a classic beauty:

Loading Slideshow...
  • 1952

  • 1927

    Six months old

  • 1928

  • Bus Stop poster

  • 1920's

  • 1948

  • 1949

  • 1948

  • 1949

  • 1950

  • 1953

  • 1954

  • 1953

  • 1956

  • 1955

  • 1961

  • 1931

  • 1955

    With director Billy Wilder fixes her hair during filming of the movie "The Seven Year Itch"

  • Some Like It Hot poster

  • 1962

  • 1950's

  • 1950's

  • 1957

  • 1956

  • 1950's

  • 1946

  • 1953

  • 1959

  • 1954

  • 1950's

  • 1956

  • 1950's

  • 1950's

  • The Seven Year Itch poster

  • 1962

  • 1961

    With Clark Gable

  • 1951

  • 1957

    With husband Arthur Miller

  • 1950's

    With Joe DiMaggio.

  • 1959

  • 1962

  • 1958

  • 1958

  • The crypt of Marilyn Monroe is seen at t

    The crypt of Marilyn Monroe is seen at the Westwood Village Memorial Park Cemetery in Los Angeles August 3, 2012. August 5th will be the 50th anniversary of the mysterious death of the Hollywood legend. AFP PHOTO / ROBYN BECK (Photo credit should read ROBYN BECK/AFP/GettyImages)

  • Photography Auction Featuring Never Before Published Photos Of The Late Princess Diana - January 2013

    AMHERST, NH - JANUARY 16: RR Auction Vice President Bobby Livingston holds a news photograph of Marilyn Monroe on January 16, 2013 at RR Auction in Amherst, New Hampshire. (Photo by Paul Marotta/Getty Images)