The man who led the Blues to FA Cup glory in May could not turn down the chance to take over the Londoners, who sacked Juande Ramos late on Saturday night after their worst-ever start to a season.
Redknapp has confirmed he will be at Spurs' home game against Bolton this afternoon rather than Fratton Park for Pompey's clash with Fulham.
He said: 'I haven't picked the team but I will meet the players in the morning and address them before the game and at half-time.
'Hopefully we can get a result. The squad has good ability but maybe a little bit of a soft centre. We need a little bit more strength and aggression if we are going to survive.
'We've got to get cracking and turn it around as quick as we can.'
Redknapp turned down the chance to join Newcastle earlier this year. But the temptation to take over a club the size of Spurs proved too much this time.
Spurs moved quickly to bring him to White Hart Lane, and Pompey reluctantly agreed to let him talk to Spurs chief Daniel Levy.
The Blues are set to receive around £5m in compensation.
Tony Adams and Joe Jordan will take charge of Pompey for today's clash with Fulham.
Also see: The darkness before the dawn? - From Pompey to Where? - latest blog post
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