Former Auburn quarterback Jeff Klein -- who was the Tigers' starting signal-caller in the 1999 season -- died this week after battling cancer. He was only 42 years old.

Klein's wife, Adrienne, made the sad announcement on Wednesday ... saying he passed away while "surrounded by his loved ones."

"At 2:36 PM this afternoon the love of my life was called home," Adrienne said. "His passing was peaceful and immediately followed the ceasing of life support."

Klein -- who played for Auburn from 1999 to 2001 -- was initially hospitalized last week after suffering serious back pain.