The rapper, whose real name is Clifford Harris Jr., and his wife, Tameka “Tiny” Cottle, held a luncheon for the foundation called “For The Love Of Our Fathers,” which honors their fathers’ battles with Alzheimer’s disease.

The Grammy winner would not talk about his arrest last month on suspicion of drug offenses, but said the inspiration for the foundation came in the aftermath of his 2007 arrest on weapons charges.

“It’s very, very personally close to our family,” said T.I., who served seven months in prison for the firearms offenses. “And while I was, you know, while I was going through my … period of hiatus, Tameka had the idea of … starting this foundation. And I thought it was an outstanding idea.”

Cottle’s father, Charles Pope, has Alzheimer’s, an irreversible neurological disorder that causes its victims to lose their memory, become disoriented and suffer personality changes. No cure is known. T.I. said his father and grandmother also had the disease when they died.

The couple said the charity will raise funds for disease research and possibly offer relief to caregivers.

Nicknamed the “King of the South,” T.I. has sold millions of albums and created the hits “Whatever You Like” and “U Don’t Know Me.” He recently stared in “Takers,” a movie about an armored car robbery gone wrong, and is working on a new album.

But his career has been threatened by legal trouble. In 2007, he was caught trying to buy semiautomatic weapons on his way to a BET Awards show. Still on supervised release for that offense, T.I. was arrested last month in Los Angeles and accused of drug offenses.

A federal probation officer in Atlanta alleges that T.I. violated the terms of his supervised release by possessing codeine, marijuana and Ecstasy, testing positive for opiates and associating with a convicted felon. The rap star would not discuss the arrest Sunday.

“We’re not going to talk much except for Alzheimer’s,” he said.