A wannabe YouTube star who shot her boyfriend dead in a botched prank they hoped would make them famous has been jailed for six months.

Monalisa Perez, 20, pleaded guilty to second-degree manslaughter for the fatal shooting of boyfriend Pedro Ruiz at their Minnesota home in June last year.

The 22-year-old victim held a 1.5-inch (3.8cm) hardcover encyclopedia in front of his chest for the prank, wrongly believing it would shield him from the bullet, but was pronounced dead at the scene after being fatally wounded.

Ms Perez, who was pregnant with the couple's second child at the time, was standing a foot away when she fired a .50-caliber Desert Eagle, one of the world’s most powerful semi-automatic handguns, at her partner.

The couple’s three-year-old child was among the 30 onlookers who watched the stunt, which was captured by two cameras, unfold.