Ukrainian boxer Vladimir Klitschko is looking to make a comeback after 17 months out of the ring with a bout scheduled in London on April 29.
The 40-year-old Klitschko said on February 16 that he thinks the chances of resurrecting his career with a victory are "50-50" against unbeaten British boxer Anthony Joshua in a heavyweight title fight.
Promoters say Wembley Stadium is sold out for the bout, with 90,000 tickets quickly snapped up.
Klitschko, who dominated the heavyweight division for nearly a decade, lost his WBA, IBF, and WBO titles to underdog Tyson Fury in Dusseldorf in November 2015.
Joshua, who is 13 years younger than Klitschko, has won all 18 of his fights by knockouts and won the gold medal at the London Olympics in 2012.
His IBF title, along with the vacant WBA and IBO titles, will be on the line.
Klitschko is also an Olympic winner, having won a gold medal at the 1996 Olympics in Atlanta.
"This is peace or silence before the storm," Klitschko told a relatively calm press conference in Cologne, Germany, with his opponent.
"As soon as our fists are flying in the ring -- nothing personal, but business for this period of time... 12 rounds or however many rounds we'll be there that night," he said.
Based on reporting by dpa and AP