Wladimir, 45, reigned as heavyweight king for nine years before losing his crown to Tyson Fury, 33, in a 2015 upset.
He would return two years later in defeat to Anthony Joshua, 32, and announce his retirement soon after, snubbing a Las Vegas rematch.
Wladimir, dad to seven-year-old Kaya Evdokia, has refused a boxing comeback in recent years and also pledged to fight on the frontline.
He enlisted in Ukraine’s reserve army in early February and has publicly pleaded with Russia to end the war.
Vasiliy Lomachenko
The masterful southpaw, 34, is one of the greatest amateur boxers of all time, leaving the unpaid ranks with a record of 396-1 and two Olympic gold medals.
It saw him fast tracked as a professional like never seen before and Lomachenko, who is married to Olena with two kids, became a three-division champ in just 12 fights.
He was beaten by Teofimo Lopez in 2020, but has won twice since and is now targeting a fight with new unified lightweight champ George Kambosos Jr.
But with talks for his return stalling, Loma was last seen holding a M16 with Ukrainian media reporting he had joined the Belgorod-Dniester Terror Defence Battalion.
Oleksandr Usyk
Usyk, who won gold at the 2012 Olympics, is a former undisputed cruiserweight king and current three-belt heavyweight owner.
He beat Joshua in September and they are contracted to an immediate rematch this year – although it remains in doubt.
Usyk, 35, had been in London last month to hold talks with AJ’s promoter to decide a date and venue for their rematch.
But now, the fearless unbeaten father-of three, who married partner Yekaterina in 2009, has enlisted with the Kyiv Territorial Defence.