Legendary actress and fitness guru, Jane Fonda has undergone surgery to replace her left knee.

According to The Mirror the Oscar-winning actress, blogged on her website before the operation.

In a post entitled "So Long Old Knee", Fonda, 72, wrote that her knee joint was to "be sawed out and in its place will go a titanium rod and ceramic joint".

She added that it had been "a strong, faithful knee" which had helped her "up a lot of steep mountains and across rugged terrain".

She recalled intimate moments with former husband Roger Vadim, who liked to kiss her knees.

She added that her doctor had written on her knee to indicate which one was to be replaced: "He neatly printed his initials - J.R.M. - even including the periods and a big arrow pointing to the knee cap.

"He said, 'Imagine if it got out that I replaced Jane Fonda’s wrong knee. Forget the career.' You betcha!"