HOLLYWOOD - Anna Nicole Smith's jailed half-brother has exposed a terrible family secret: His youngest sibling was once shot in the head by his mom Virgie Arthur's gun.

Larry Dale Hart, who is serving time in a Texas prison for aggravated and sexual assault, has revealed his younger brother Donny was accidentally shot when he was just three.

Speaking exclusively on TV news show Insider last night, Hart recalled how his brother was left with a severe head wound after a gun in his mother's purse went off by mistake as he played with it.

He said, "Donny went to climb on the bed to knock the purse down and the gun went off inside the purse. We saw blood coming out."

Arthur, a former police officer, ordered all her kids to get into her car and she dashed Donny to hospital, where, according to Hart, she went into shock.

He adds, "They had to give her some kind of tranquillizers... She never talked about it after that."

Arthur hit the headlines after her daughter's tragic death in February when she challenged burial rights and then custody for Smith's daughter.