The Undertaker officially announced his WWE retirement at Survivor Series in November last year. 

His incredible career came full circle at the event, as he stepped away from the ring exactly 30 years after his debut in 1990.

While The Phenom announced his retirement at Survivor Series, his last match actually came seven months prior to that, at WrestleMania 36. 

Undertaker furthered his impressive record at The Show of Shows by beating AJ Styles in a Boneyard Match, going out on a high. 

But Mark Calaway - the man behind the character - has since revealed it was during that match that he realised it was time to retire. 

"About halfway through that night with AJ, I knew that was it for me," he told Sports Illustrated last week.

"It became really obvious throughout the course of that night that I could no longer physically do things the way I want to do them, and I refuse to ever shortcut our fans."

Undertaker reveals when he knew it was time to retire

'Taker went on to reveal that to get in shape for WrestleMania, he usually has to start training around October. 

He purposely didn't do that this year, confirming that he's at peace about missing The Show of Shows in the future. 

Usually around October, I start getting my body ready for WrestleMania. I didn’t train a lot this year, purposely building in a safety net that way. So I was at peace with everything.

WWE fans were perhaps expecting Undertaker to make an appearance at WrestleMania 37. After all, it was the first event with a live crowd in over 13 months. 

The Undertaker retired at Survivor Series last year

Calaway worked his last match and even retired when no fans were present last year, so many were hoping to see him at Raymond James Stadium a few weeks ago. 

That didn't happen, of course. While we never say never in WWE, it does look like The Undertaker is done for good - and he knew it over a year ago at WrestleMania 36.