United Kingdom, Jan. 23 -- Martha Stewart has dismissed speculation that she has had plastic surgery.

The 84-year-old lifestyle mogul is puzzled that people don't believe her denials about going under the knife because she is "the most honest person on earth".

Discussing the launch of her skincare line Elm Biosciences, Martha told People: "Everybody insists that I've had plastic surgery and I have not ever had plastic surgery. I'm the most honest person on earth - but if they won't take my word for it, I don't know.

"How can they not take my word for it? That's the truth."

Stewart recalled how she had to have some cosmetic work done after receiving a facial injury from one of her dogs, although she doesn't consider that to be plastic ...