While the phrase is relatively new thanks to Tony Khan, the Forbidden Door has been a Saloon-style swinging gate for years now. But generally, the WWE seems so rigid about working with other promotions that it’s hard to remember that they do from time to time. But the company and plenty of other promotions have made joined up from time to time, whether they wanted to or not.

RELATED: 10 Forbidden Door Moments That Can Happen In WWE This Year

As the pro wrestling world grows closer than ever, fans are hoping the walls between promotions will continue to crumble. Dream matches, unimaginable surprises, and special events are all a very real possibility these days, even if fans have forgotten the few times the door has swung open in the past.

10 Chris Jericho On Broken Skull Sessions

The internet was rocked back in the spring of 2021 when a familiar countdown hit the Broken Skull Sessions. Sitting across from Stone Cold was the first ever WWE Undisputed champion - AEW’s Chris Jericho!

The two spoke at length about Jericho’s legendary career and didn’t shy away from his time in New Japan or joining and helping to start AEW.

9 Jushin Thunder Liger Vs. Tyler Breeze

As NXT was gearing up for its first TakeOver of Brooklyn, Tyler Breeze was flummoxed that he hadn’t been given a match against a worthy competitor.

RELATED: Kevin Nash And Jushin Thunder Liger & 9 Other Crazy Wrestling Pairings We've Never Heard Of

Commissioner William Regal used his vast network of connections to bring in the legendary global superstar, Jushin Thunder Liger. For the first and what was his only time working for WWE, he came to Brooklyn and took Tyler to the limit.

8 Hardcore Country At The Royal Rumble

In a lot of ways, Mickie James will always be a member of the WWE family and a huge goalpost for anyone to aspire to male or female as far as careers go. But she has also spent a considerable amount of time in other promotions like Impact.

In 2022, she was the Impact Women’s Champion and made history by being the first ever non-WWE women’s champion to enter the Royal Rumble. She was even able to walk through the Forbidden Door using her Impact theme and gimmick.

7 Billy Gunn Joins DX In The Hall

By 2019, Billy Gunn was considered a legend and had earned his spot as a WWE Hall of Famer, alongside his brethren in D-Generation X. But there was one small issue by the time the 2019 Hall Of Fame induction ceremony - The One was already part of AEW.

However, he was still allowed to join the fun and take his rightful place, and some gentle joshing from his buddies about his new company.

6 Ric Flair Gets His Horsemen Ring / Christian Comes To TNA

Gunn wasn’t the first Hall Of Fame inductee to be inducted while working for another promotion, that distinction goes to The Nature Boy. When the Four Horsemen were inducted in 2012, it wasn’t going to be a party without The Nature Boy, but he was stylin’ and profilin’ for TNA at the time.

RELATED: 10 Wrestlers Ric Flair Couldn't Get Over

So WWE reached out to Bruce Prichard, also at TNA at the time to broker a talent trade. For some reason, Dixie wanted Christian, but not to wrestle (that’s the “some reason” part), but to return, say hi, and announce that Sting was going into their Hall Of Fame.

5 Triple A Rumbles In The Alamo

With WCW kicking WWE’s derrière in 1997, the company was looking for ways to compete - and that meant a partnership with other promotions. The WWE had tried to make inroads into Mexico and Triple A. The company was a huge part of the Royal Rumble 1997 from San Antonio.

But the issue was that you couldn’t just insert masked Luchadors and expect them to take off (pardon the pun) the same way that WCW Cruiserweights had done. It was the first of only a few times that Triple A and WWE combined talents.

4 WWE Vs. WCW For The ECW Title

It wasn’t on purpose, but towards the tail end of the Monday Night Wars, WCW snagged a small victory when they signed the amazing Mike Awesome away from ECW. But The Gladiator was ECW Champion at the time and there was zero chance Paul Heyman was going to allow Awesome or WCW to pull another Madusa.

He acted quickly and litigiously and stopped Awesome from appearing on Nitro with the belt and was able to get Tazz back from WWE for a week, long enough to take Awesome out and put over Tommy Dreamer.

3 Rob Van Dam Takes Raw To The Extreme

After Jerry Lawler invaded ECW, The King (and by extension, WWE) took a shine to Mr. PPV, Rob Van Dam. While his run on Raw was brief, RVD was able to showcase his talents to a wider audience.

During his run, he teamed up with Lawler against The Headbangers and took on Flash Funk as well Jeff Hardy.

2 SMW Tag Titles Defended At Survivor Series

According to Bruce Prichard on Something To Wrestle, one of the caveats it took for Jim Cornette to finally come to the WWE and manage Yokozuna was that he wanted to showcase his Smoky Mountain Wrestling promotion.

He did receive in all sorts of ways, up to and including the SMW Tag Team Titles being defended at the 1993 Survivor Series. Cornette’s team, The Heavenly Bodies challenging Corny’s long-time rivals, the Rock N’ Roll Express. As usual, The Express fell victim to Cornette and his tennis racket, helping the Bodies win the belts.

1 The Machine Gun’s 2022

One of the most, if not the most recent instance of WWE opening The Forbidden Door was when Luke Gallows and Karl Anderson returned to back AJ Styles against The Judgment Day.

He was at the time and up until the 2023 Wrestle Kingdom the NEVER Openweight Champion. He became the first ever contracted WWE wrestler to hold the title and defend it at the big January 4th show.