Jamie Redknapp has signed a six-month contract with Southampton after Tottenham allowed the midfielder to leave on a free transfer.
The 31-year-old passed a medical on Monday and will now link up with father Harry at St Mary's.
"I am so excited about this - it's a great club to come to and a big challenge for me," he said.
"The fact that I am helping my Dad out comes into it a little bit but the main thing for me is to be playing again."
Redknapp joined Spurs from Liverpool in 2002 and made 53 first-team appearances for the club.
He was appointed club captain following the departure of Teddy Sheringham in 2003 but he has made only nine league starts this season.
"Michael Carrick is playing well in midfield and I did not see myself getting back in," explained Redknapp.
"I really think this will give me a new lease of life. It has given me a lift already and I cannot wait for Wednesday night (when he is expected to make his debut against Fulham)."
Redknapp also thanked Spurs for allowing him to leave.
"They were great about it and (manager) Martin Jol even said when I finish playing to come and talk to him about a coaching role.
"He was very keen for me to get involved in the coaching staff nextseason and that was very flattering.
"But in my heart I knew I had some more football left in me and was not readyto give up playing just yet.
Ledley King, who has led the side in Redknapp's absence from Spurs first team, has been confirmed as the new permanent captain by the White Hart Lane club.
"I've learned a lot from Jamie and we all wish him well at Southampton," said King.
"It is an honour to be captain, we've got a great side with the best team spirit we've had for years.
"It is a good time to be playing for the club and everyone is enjoying it."
Tottenham chairman Daniel Levy paid tribute to Redknapp.
"Jamie has been an outstanding ambassador for our club - during his time with us he has always shown commitment and enthusiasm," he said.
"He proved to be an excellent club captain with his positive attitude and fostering of team spirit. We would like to thank Jamie and wish him well at Southampton."
Saints boss Harry Redknapp has already been busy in the transfer market as he attempts to save the club from relegation.
Calum Davenport has joined on loan from Spurs while Abel Xavier and Alex Nyarko are on trial.
Redknapp is also expected to have a significant sum to spend on players following the departure of James Beattie to Everton for £6m.