Having already played identical twins in The Man in the Iron Mask, Leonardo DiCaprio is set to play twin brothers again in Johnny Eck.

Except this time there's a twist. Make that a half twist.

The Titanic heartthrob has, according to Daily Variety, signed on to star as real-life siblings Robert and Johnny Eckhardt, the latter of whom was born without legs and achieved a modicum of fame for his appearances in carnivals, movies and TV shows.

Billed as Johnny Eck, he was best known as the half-boy hero of Tod Browning's 1932 cult horror classic Freaks.

His brother, Robert, turned out to be completely normal.

It's expected to be a very demanding, physical role for DiCaprio, who has always preferred tackling more offbeat characters (see What's Eating Gilbert Grape?) rather than larger-than-life types.

The movie, which is being produced by Hollywood vet Mark Gordon, charts the relationship between the brothers and how they successfully overcame the exploitation of Johnny to lead normal lives.

Born 20 minutes after his twin brother in 1911, Johnny Eck stood only 1 foot, 6 inches tall and had no lower torso or legs. He joined the sideshow circuit, was "discovered" by talent scouts at a Canadian exhibition and soon found himself in Los Angeles with his first role in Freaks.

Shocking the world when it was released in 1932, Browning's film billed itself as "the strangest, the most startling human story ever seen." The movie explored the lives of sideshow carnival "freaks" and a love affair that emerges between a dwarf named Hans and a "normal" trapeze artist named Cleopatra.

Eck played Johnny the Half-Boy in the film that costarred such memorable characters as the Human Torso, Hercules, Pinhead Girl, the Siamese Twins and Frances the Turtle Girl.

In the late 1930s, Eck had unbilled roles in two Tarzan movies and found himself the centerpiece of Ripley's Believe It Or Not Odditoriums where he was displayed as "The Most Remarkable Man Alive!" He even had a, um, small role in the 1960s sitcom The Beverly Hillbillies.

Despite his birth defect, Eck became a successful artist, living a long life with his brother in Baltimore, where he died in 1991 at the age of 79.