The Undertaker helped Randy Orton get to where he is in WWE today.
Back in 2005, the pair had a brilliant storyline that really put over 'The Legend Killer' as one of pro wrestling's biggest stars.
It all started with a slap on SmackDown and saw the two go head-to-head at WrestleMania before concluding nine months later inside Hell in a Cell at Armageddon.
Undertaker vs Orton was one of the greatest feuds in WWE history - but according to 'The Viper' himself, he nearly messed it all up before it had barely started.
Speaking on an upcoming episode of 'WWE Untold: The Phenom and The Legend Killer', he shared a story about missing WrestleMania rehearsals with Undertaker.
Orton calls it 'one of my biggest regrets in the business' and went on to thank 'Taker for how cool he was in dealing with the issue that day.
"I’ve got a little side story, it doesn’t really show me in the best light. I was 24 I was a bit of a p***k back then," Orton began.
"We have the Hall of Fame and we have WrestleMania. The morning of the Hall of Fame we have rehearsal.
"My father, John Laurinaitis, Ricky ‘The Dragon’ Steamboat, one of the referees and The Undertaker were all part of rehearsal. There was supposed to be six men there. I was supposed to be the sixth.
"Let’s just say I got into a little trouble and didn’t get a lot of sleep… just in case my kids are watching.
"This is my second WrestleMania, I’m 24, I’m being given the world. My f***ing dad is there, ‘Taker is there. But I get down there just as they’re finishing up."
Orton missed rehearsal for the biggest match of the year. So, what did Undertaker do? Did he chew Randy out? Rat on him to the boss? Make it a big deal?
Nope, 'Taker didn't do any of that.
"I worked with the Undertaker for nearly a year and it all started with me missing rehearsal for the biggest match of the year," Orton continued.
"A lot of people may have opinions of me from early in my career, but nobody considers myself as more of an a**hole than I do.
"So 'Taker, if you're watching: Thank you for not b****ing me out, cursing me out or chokeslamming my a** to hell after I missed that rehearsal.
"That's one of my biggest regrets in the business, letting you down that day.
"I see now how wrong that was and when I’m in the locker room trying to teach the young guys and girls about the little things I always go back to where I started.
"If it wasn’t for Undertaker, none of this would have ever happened."
Brilliant. Yet another story that proves just how much of a WWE legend The Undertaker really is.