The clubs confirmed the move today (January 26) and Kanu could make his Cobblers debut in a League Two game against Salford at Sixfields on Saturday (January 29).
Kanu started just one match for Posh this season, a 3-0 Championship defeat at Swansea City in October. He has just returned from the AFCON Cup, but he failed to make an appearance for Sierra Leone who were knocked out in the group stages.