The transfer, agreed in principle earlier in the year, has been concluded with Chopra committing himself to Cardiff City.
Chops had two loan spells at Ninian Park last season. He left Cardiff for Sunderland two years ago but it never really worked out and now he's back.
There is talk of it being a record transfer fee paid by Cardiff but it's unsure whether City ever received all the money due from Sunderland for the original transfer.
Either way Chopra joins Ross McCormack in signing a new deal in the last week,