Phillips admits he blundered when celebrating a goal for Birmingham against Saints five years ago.
Phillips, 40, said: "I had six great years with Saints as a teenager and two more after coming back from Sunderland. I came off the bench and got Birmingham's winner with a couple of minutes to go and it was just a reaction. I should not have celebrated that goal.
"I have so much fondness for Southampton. The fans and the club always treated me brilliantly."