The Belvedere Torso is a Greek marble statue with no arms or a face.
According to the Vatican Museums website, the statue "came into the Vatican collections between 1530 and 1536."
The Renaissance painter and sculptor Michelangelo was known to admire the piece during his lifetime, to the point where the style in which the Belvedere Torso was made was given the nickname "The School of Michelangelo".
It inspired Michelangelo's depiction of Adam on the ceiling of the Sistine Chapel.
The Torso will be shown alongside the Elgin Marbles, a collection of Greek statues, and several other pieces at the British Museum from March 26.
The exhibition is called: "Defining Beauty: The Body In Ancient Greek Art."
Neil MacGregor, Director of the British Museum, said: "This is a loan of astonishing importance. It is what everybody regards as the great Greek body... the body people want to have."
"[It's] one of the great sculptures of antiquity that shaped how people thought about the human body."
"This exhibition will be a celebration of the beauty and ideals of ancient Greek art.
"Some of the most beautiful works in the world will be brought together for the first time in a narrative exploring the highest achievements of ancient Greek artists and philosophers, exploring what it is to be human."