Sources close to Villa insist it is a case of "dotting the i's and crossing the t's" before they can formally announce the capture of Bent.
It is hoped Bent will be unveiled at a Villa Park press conference later this afternoon although this has still to be finalised.
Bent's arrival will smash Villa's transfer record of £12million paid for James Milner and Stewart Downing when signing from Newcastle and Middlesbrough respectively.
The deal could eventually be worth £24million to the Black Cats with add-ons.
Villa fans have often craved a marquee signing and 26-year-old Bent will fit the bill.
He has scored 81 Premier League goals in the last five seasons - a figure only bettered by Didier Drogba and Wayne Rooney with 82 apiece.
Bent's signing will take Villa's potential spending in this transfer window close to the £30million mark after already signing Lyon midfielder Jean Makoun for £6million.
Villa boss Gerard Houllier is still interested in Blackpool midfielder Charlie Adam and is also looking to bring in a new left-back.