A South African airline came up with a novel promotion this week for male passengers traveling with multiple wives.

Kulula Airlines, based in Johannesburg, is offering a free ticket for a man's fourth wife if the entire family flies together between the city and Cape Town.

The ad reads, "Not only will you get a great deal on kulula.com flights for your first three wives, but your fourth wife will fly free, mahala, on the house."

The stunt, which runs until April 30, coincides with South African president Jacob Zuma's marriage to his fourth wife over the weekend. Zuma has been married six times in total, but one of his wives committed suicide in 2000, and he divorced his second in 1998.

Men looking to take advantage of the conjugal offer simply have to present a pre-bought ticket, proof of marriage and ID at the Kulula counter, and the fourth wife's ticket will be refunded.

The promotion reads, "Inspired by regular VIP travelers with sizable spousal entourages, the offer is open to all fourth wives when the family travels together on the Jo'burg to Cape Town route."

In 2010, the airline used one of its planes -- dubbed "Flying 101" -- and painted the exterior to show where various parts, such as the black box, were located.