Former Blur members Graham Coxon and Alex James both turned up for the first night of Damon Albarn's opera Monkey: Journey To The West on Wednesday night.
Both Coxon and James told Newsbeat how impressed they were with the show.
Albarn admitted to Newsbeat last week that he had patched relations up with Coxon, who left the band in 2002, and had even been "hanging out" with him.
Monkey will be housed in a specially-made tent next to the O2 in London for the next month.
"I loved it, loved it," said Coxon. "I was riveted, lovely music, how the set looked and the dancing of course. He's very clever, I was always rather in awe of Damon's talents from a young age, really it's his staunchness about music and his energy."
James was in agreement, saying: "It was totally brilliant, utterly astonishingly amazing, it was one of the best pieces of theatre I've ever seen. It was better than Power Rangers."
[it's] not as easy as putting on a pop concert
"It's good tunes, but you've [also] got people putting there - what was that woman doing putting her head up her bottom? - that was amazing.
"Just a huge splurge of music, vision, twirly strings and dragons, it's utterly transporting and everything theatre should be."
Whether Albarn's former bandmates are biased or not, it's hard not to be impressed by Monkey - it combines martial arts, singing and a few laughs with the type of acrobatics that leave you confused as to how anyone can contort their body like that.
There's plenty of animation from Jamie Hewlett throughout, which you'll instantly recognise from Gorillaz or his and Albarn's BBC Olympics coverage this year.
First night nerves
Damon Albarn and co-creator Jamie Hewlett joined the cast on stage at the end where they got a standing ovation.
Jamie joked afterwards that the audience reception was planned, saying: "It's because we had these little heaters in the seats that we turn on just at the end and everyone screams and stands up - guaranteed standing ovation."
Albarn was a little less jovial after the show. "[I'm] relieved," he said. "Generally just relieved because there's so much detail that you have to consider and seeing it as a finished thing is hard, so [I'm] just relieved."
He admitted he enjoyed the bow at the end, and explained that he instigated the cast running forward a number of times with a big smile on his face.
"It's nice just to acknowledge everybody and be on there with them and enjoy that moment, you've got to enjoy it when it happens."
Monkey: Journey To The West opened in Manchester last year
Hewlett said he was nervous beforehand: "I can't even watch it, one of our martial arts experts has a broken hand and is being rushed to hospital now and that's what happens every night so that's how nervous I am."
"I saw lots of mistakes but I think the public didn't spot them," explained Albarn. "I think it went well, everyone was happy. It was almost perfect but there's lots of problems, every night is fraught with danger and I see all those things.
"The subtitles computer went down half way through, someone trying to figure out how to fix the computer in three seconds, not as easy as putting on a pop concert," he joked.
The opera is in Mandarin so there are two screens either side of the stage with subtitles - however, reading them means taking your eye off the performance.
The production is on at the O2 after their short stint at the Royal Albert Hall. However, they're both keen to stress it's not really at the O2, it's in a tent next to the O2.
They call it Monkey's World, and it's a huge marquee with the theatre, foyer and a restaurant - serving Chinese dishes at £28 a head - inside.
You can also have your foot massaged, which Albarn told us is something the Chinese do on a Friday night rather than head to the pub.
Inside it has black walls, traditional red lanterns and prints of Jamie Hewlett's artwork of Monkey and the other characters from the opera.
"If we make a profit great if not then whatever, it's good being poor," said Hewlett. "I've been broke so many times it doesn't really bother me anymore."
Monkey: Journey To The West is on at the O2 until 5 December.