It was a joke made in an episode of The Simpsons back in 1996: Cypress Hill and the London Symphony Orchestra performing together.
Now, 28 years later, the epic collaboration is no longer a cartoonish work of fiction.
The hip hop group teamed up with classical musicians to put on a show at the Royal Albert Hall in London on Wednesday night.
"It's a dream come true, a collaboration only The Simpsons could have predicted," the band said in a statement announcing the show in March.
Here's a few snippet from the show shared on Cypress Hill's Instagram account:
Decades in the making
The band appeared on an episode of The Simpsons called Homerpalooza (for anyone wanting to look it up, it's season 7, episode 24).
Homerpalooza first aired in May, 1996.
It features a scene backstage at a fictional music festival where cartoon iterations of Cypress Hill find themselves collaborating with the London Symphony Orchestra.
The scene went for less than a minute, but it had a lasting impact.
"It's been something that we've talked about for many years since The Simpsons episode first aired," Cypress Hill's B-Real told UK broadcaster the BBC.
The concert came years after the band and the orchestra joked about the idea on social media.
Cypress Hill tweeted a quote from the episode, to which the London Symphony Orchestra's official account replied: "We mostly play classical… but we'll give it a shot."
"We started speaking with them back and forth," B-Real told the BBC.
"And they seemed to be interested … so we kept carrying on the conversation.
"It took a few years, but we finally got it."
