The 36-year-old Defoe, who has scored 162 goals in England’s top flight, has joined Rangers from Premier League club Bournemouth in an 18-month deal.
Rangers, managed by former England midfielder Steven Gerrard, are currently level on points with arch Glasgow rivals and reigning champions Celtic at the top of the table.
“I’m delighted to be able to welcome Jermain to Rangers,” said Liverpool great Gerrard. “He is an exceptionally talented striker and vastly experienced footballer who has scored goals at every club where he has played.”
Defoe was not the ony player on his way to Ibrox in a loan move from a south coast Premier League club on Sunday.
Southampton midfielder Steven Davis returned to Rangers for a six-month stint, having previously made over 200 appearances in a four-year spell with the Gers that saw him win eight major trophies, including three league titles.
“He has previously captained the club and been captain for his country and Southampton, so we welcome yet another leader into our dressing room,” said Gerrard.