Former super-middleweight world champion Mikkel Kessler has announced he will return to the ring this year.
The 38-year-old Dane, who won five world titles, has not fought since losing a rematch to Britain's Carl Froch in 2013, and said in February 2015 he was in a "state of retirement".
He will re-enter the super-middleweight division, which includes British IBF world title holder James DeGale.
"I want to prove that I can become the best again," said Kessler.
"I've missed the training camps, and I've missed the focus you get from boxing - to have one goal, and to do your best to achieve it."
Kessler has yet to name a date or an opponent for his return.
DeGale, 31, failed in his bid to unify the division in a controversial majority draw with Sweden's Badou Jack in January.
Jack subsequently vacated his WBC belt to move up to light-heavyweight, after being ordered to defend his title against Briton Callum Smith.
That title remains vacant, while Germany's Tyron Zeuge holds the WBA belt and Mexico's Gilberto Ramirez is the WBO champion.