Tony Bellew says he was "born ready" and is willing to face undisputed cruiserweight world champion Oleksandr Usyk.
'Bomber' fired a tweet out as soon as the new World Boxing Super Series champion called him out.
"Usyk I was BORN READY!! Let's get this done!!" was the simple response to the Ukrainian, who was in agreement along with promoter Eddie Hearn.
Usyk made history becoming the first to hold four cruiserweight world titles after outclassing Murat Gassiev in the final of the WBSS, in Moscow, on Saturday.
Bellew, who is currently on honeymoon, has said it will take "something absolutely ridiculous" to box again after back-to-back wins over David Haye.
The 35-year-old has put Tyson Fury, Andre Ward and Adonis Stevenson on his shortlist, but with Usyk ready to move up, he could overtake them all.
Hearn has said a fight with Fury "isn't going to happen any time soon", Ward is still in retirement, while Stevenson is still at light-heavyweight, where he handed Bellew his only defeat back in 2013.
"Hey Tony Bellew, are you ready?," Usyk told ITV Box Office, after the fight.
"If he doesn't want to go down, I will go up for him. I will eat more spaghetti for my dinner!"
Usyk's one-sided 120-118, 119-109, 119-109 win over Gassiev saw him add the WBA and IBF titles to his WBC and WBO versions, surpassing Evander Holyfield, who was the undisputed cruiserweight champion when only three titles were available.
Holyfield went on to become a world heavyweight champion and, earlier this year, Usyk admitted he will step up and is happy to fight in the United Kingdom.
"First of all, I like Britain because that is where boxing was born," he told skysports.com in January.
"The fans over there still follow me and watch me, so I will always try and show them my best."
Bellew will be back from honeymoon this week and will be reunited with another former cruiserweight king, Haye, as part of the Sky Sports Box Office team for the Dillian Whyte vs Joseph Parker event.
Watch Dillian Whyte vs Joseph Parker with Katie Taylor, Dereck Chisora, Joshua Buatsi and Conor Benn all on the undercard, live on Sky Sports Box Office, from The O2, Saturday, July 28.
You can book via your Sky remote, via sky.com/boxofficeonline here and even if you aren't a Sky subscriber you can book and watch it via skysports.com/boxofficelive.