It appears Angelina Jolie's love of tattoos is rubbing off on partner Brad Pitt.

The 44-year-old unwittingly flashed his latest etching during a day out with his adopted sons Maddox, six; and Pax Thien, four.

On first glimpse, it looks like one of Brad and Angelina's many children have been drawing on their famous father's back with a marker pen.

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Tattoo me: A gust of wind flashes Brad Pitt's new tattoo at Monaco's heliport

Brad's unusual back tattoo comprises groupings of horizontal black lines, with bizarre boxed shapings below.

The strangest combination appears to be inspired by a map of the levees in New Orleans, which was ravaged by Hurricane Katrina in 2005 when the systems failed.

More than 1,800 people died in the storm and during the rescue debacle which followed, mostly the poor, sick and disadvantaged. Costing around $81billion, it was also the costliest disaster in U.S. history.

Since Hurricane Katrina, Brad and Angelina have bought a home in the Louisiana city and the actor has been heavily involved in local building projects.

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Inspiration: Brad Pitt is passionate about helping New Orleans get back on track. It was ravaged after the levees failed to work property after Hurricane Katrina

This latest etching joins previous markings of Otzi the Ice Age caveman on Brad's inner left forearm and a Sanskrit Buddhist blessing for Cambodian-born Maddox on his lower back.

Brad, who has been dating Angelina, 33, since 2005, also has the actress' birthdate written in Khmer on his stomach.

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Daddy's boy: Devoted father Brad helps his adopted son Pax into the helicopter

His girlfriend Angelina has over a dozen tattoos, including the geographical co-ordinates for all four of her children and the Latin proverb "quod me nutrit me destruit" (what nourishes me destroys me).

The actor's tattoo was put on display as he boarded a helicopter in Monaco for a boys' day out with Maddox and Pax.

The swirling wind at the heliport lifted up Brad's shirt, exposing his bizarre new etching for the first time.

Meanwhile, heavily pregnant Angelina - who is rumoured to be expecting twins - had a girls day with adopted daughter Zahara Marley, three, and Shiloh Nouvel, who turns two on May 26.

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Girls day out: Angelina Jolie, in her trademark black, cuddles up to Shiloh Nouvel as she guides Zahara through the streets of Monaco

Carrying blonde-haired Shiloh and holding Zahara's hand, Angelina browsed childrenswear stores of the principality.

The couple are currently staying with their four children and two nannies in Microsoft co-founder Paul Allen's Villa Maryland in St Jean Cap Ferrat in the south of France while are hunting for a permanent Gallic base.

Angelina is keen to have a French home - in addition to the houses they have in New Orleans, LA, and Cambodia - in preparation for the birth this summer.

Mini me: There's no mistaking the parentage of little Shiloh