The former Chelsea and Barcelona star underwent a medical with the club on Thursday and joins an attacking line-up which already includes Robbie Keane, Jermain Defoe, Peter Crouch and Roman Pavlyuchenko.
"He's player I've always admired," said Redknapp.
"He can play several positions and is a very clever footballer. "It was his decision to come to us. I rang him and left a message on his phone and he came back to me and said I want to come to Tottenham. He gives us lots of options. He is a top player."
Redknapp also confirmed Birmingham were in talks for Russian striker Pavlyuchenko but added: "We're not keen to sell him. We're happy with him.
"Technically he's a terrific player."
Source: PA
Source: PA