Time magazine announced the at the forefront of the movement as their Person of the Year on Thursday.
The fast-growing social , which encouraged women to speak up about their experiences of sexual harassment, assault and rape against Hollywood heavyweights including Harvey Weinstein, Kevin Spacey and Dustin Hoffman.
But social media users were quick to notice that as well as the women featured in full, there was also an anonymous arm in the shot, on the right-hand side of the cover.
Many believed that the mystery elbow alongside Ashley Judd, Taylor Swift, Susan Fowler, Adama Iwu, and Isabel Pascual was intended to represent all the people who have experienced sexual assault or harassment, and haven't been able to come forward.
Time magazine's editor-in-chief Edward Felsenthal appeared on US talk show Today to announce the cover and confirmed the arm was that of one woman who wanted to remain anonymous.
"The image you see partially is of a woman we talked to," Felsenthal said.
"A hospital worker from the middle of the country, she shared her story with us but doesn't feel like she can come forward without threatening her livelihood."
A statement on behalf of the magazine said: "She too is a victim of sexual harassment but was there anonymously, she said, as an act of solidarity to represent all those who could not speak out."
