Gosport-born Whatmough made 136 appearances for Pompey before the move north, having joined their academy after leaving rivals Southampton.

"To finally get it done and announced is a proud moment," Whatmough said.

"There were no grey areas. As soon as I spoke with Mal [Brannigan - chief executive] about extending my stay, it was always about getting it done as soon as we can."

Whatmough scored his first Latics goal of the season on Saturday, netting the winner in Wigan's important 1-0 victory over fellow Championship strugglers Huddersfield Town.

"He has shown both before my arrival and in his short time with me the ability that he has," boss Shaun Maloney told the club website.

"He works hard in training, is very physical and is great in the air, as we saw with his winning goal at the weekend. He is also calm under pressure and is developing into a real leader within our back line."