Former WWE superstar Cesaro made his All Elite Wrestling debut during the company's Forbidden Door joint pay-per-view with New Japan Pro Wrestling on Sunday (June 26) night at the United Center in Chicago, Illinois.
Cesaro, wrestling under his real name, Claudio Castagnoli, was revealed to be Zack Sabre Jr.'s mystery opponent handpicked by the injured Bryan Danielson, as well as the newest member of the Blackpool Combat Club, joining Danielson, Jon Moxley, William Regal and Wheeler Yuta.
The Lucerne, Switzerland native left WWE in February after the two sides failed to reach an agreement on a new contract.
PWInsider.com reported that Castagnoli's contract had expired in February and the company offered an extension on his previous deal, which was declined, according to a source with knowledge of the negotiations.
Castagnoli initially signed a developmental contract with WWE in 2011, having gained notoriety for several promotions including Ring of Honor, Pro Wrestling NOAH, CZW and CHIKARA, both as a singles competitor and as part of the Kings of Wrestling tag-team alongside Chris Hero.
The 41-year-old made his WWE main roster debut as Antonio Cesaro in 2012 -- with WWE later dropping the first name -- and won the United States championship several months later.
Cesaro was also a multi-time WWE Raw and SmackDown Tag Team champion alongside Sheamus, Shinsuke Nakamura and Tyson Kidd during his stint with the company.
The Swiss native last appeared on WWE television on February 11, losing a match to Happy Corbin on Friday Night SmackDown.