Steve Bruce has resigned as Sheffield Wednesday manager, Sky Sports News understands.
It comes after he confirmed over the weekend that he had held talks with Newcastle to become Rafael Benitez's successor.
The 58-year-old led Wednesday to a 12th-place finish in the Sky Bet Championship last season after taking over from Dutchman Jos Luhukay in January.
Newcastle made an official approach for Bruce last week and on Saturday, Bruce told Sky Sports News: "It's in the hands of the two clubs at the moment. There is nothing really to talk about until the two clubs reach some sort of a compromise.
"I have had a conversation yes.
"It has happened so quickly that I have to take stock of the situation, it's in the hands of both clubs and I will see where it develops over the next 24 to 48 hours.
"It's football and has come from nowhere in the last two or three days, so we will see what this weekend brings."
Sky sources reported last week that Sheffield Wednesday were holding out for a compensation fee greater than originally expected by Newcastle, which held up the potential deal.
Newcastle-born boss Bruce previously managed the Magpies' North-East rivals Sunderland.
Previous Newcastle manager Benitez left the club following the expiry of his contract and took charge at Chinese Super League side Dalian Yifang.
The Newcastle squad is currently in China without a manager, preparing to take on Wolves in the Premier League Asia Trophy.