WWE fans shocked and surprised after hearing what Triple H said off-mic during The Rock's promo

WWE fans are shocked after hearing Triple H's off-mic comment about The Rock during his promo at an eventful WrestleMania press conference.

In Las Vegas, ahead of the Super Bowl in Sin City on Sunday, WWE put on a 'Kick-Off' event to hype up WrestleMania 40 in Philadelphia.

Real life relatives The Rock and Roman Reigns were present in what many felt was to announce a stunning main event match for the WWE Undisputed Universal title at 'The Show of Shows'.

The Rock, who recently joined the TKO board which heads up WWE and UFC, made a shock return at Smackdown on Friday, where it was heavily implied that he would be taking on the Tribal Chief.

Despite immediately signalling his intentions, Royal Rumble Cody Rhodes had seemingly allowed the People's Champion to take the match.

But on Thursday, the 'American Nightmare' announced that he had in fact chosen a rematch against Reigns as he bids to "finish the story" on the grandest stage.

After a verbal exchange, things escalated when Rhodes brought up Reigns and The Rock's family, leading to him being slapped and all hell broke loose.

The whole angle was a throwback to the Attitude Era, with Triple H even adding to the chaos.

The 14-time world champion, now chief content officer of WWE, appeared to quip that The Rock was "crossing the f***ing line" during the segment.

'The Game' didn't have a microphone at the time but fans definitely heard it.

One fan wrote: "HHH cooked so hard with this even Rock is marking out in the middle of their segment."

Another said: "You can even hear Triple H in the background saying The Rock is crossing the f'n line. Even Trips was Attitude Era 'ing it up."

A third commented: "He pointed simultaneously saying '….crossing the f’n line' clearly eluding to Rock."

A fourth added: "The nostalgia hits hard, love the Attitude Era vibes!"

The Rock would then tell Triple H to "f***ing fix it" in a heated, expletive-filled backstage interview as fans speculate on what will happen going forward.

What is confirmed, though, is that Reigns and Rhodes will be locking horns again at WrestleMania after Triple H made the announcement.