The 67-year-old Dutchman, who had turned down owner Ellis Short's offer of an extended stay at the Stadium of Light in the wake of his successful Barclays Premier League survival mission, has belatedly given the Texan and sporting director Lee Congerton the answer they wanted all along after a re-think.
Advocaat said: "After a lot of discussions with Ellis and Lee, they convinced me that I am the right man for the club.
"It was a great feeling to be part of Sunderland in the last few months.
"The experience was something very special and after talking with Lee, Ellis and of course my family, we all agree it is the right decision."