A hospital spokesperson in Santiago says the man's thick layer of fat acted in the same way as a bulletproof vest, taking the impact of the shot.

La Cuarta newspaper reports Omar Alegria Campos, who's 33, was driving his bus in the San Bernardo area of Santiago when an armed man got on and started robbing passengers.

Alegria stopped the bus and switched on his emergency lights to alert the police. He then tried to grab the man's weapon.

The attacker fired twice. The first bullet smashed the windscreen and the second lodged in the bus driver's stomach.

Despite the wound, Alegria managed to throw himself on top of the robber, stopping him from escaping.

A passing police patrol arrested the 29-year-old attacker. They also took Alegria to El Pino Hospital, where doctors extracted the bullet and sewed up the wound.