Adele felt "highly emotional" and "incredibly nervous" the night before her delayed Las Vegas residency began on Friday.
The Hello singer originally postponed the residency the day before it was due to begin in January because the show wasn't ready, and it is finally due to open at The Colosseum at Caesars Palace on Friday.
Adele, 34, admitted in a lengthy Instagram post on Thursday night that she was "more nervous" than she had ever been before a show.
"I'm feeling all sorts as I write this. I'm highly emotional, incredibly nervous but can't sit still because I'm so excited," she wrote alongside a picture of her rehearsing in the auditorium. "I always get scared before shows, and I take it as a good sign because it means I care and means I just want to do a good job."
The Rolling in the Deep hitmaker then speculated why she might be feeling so anxious and acknowledged the postponement earlier this year.
"Maybe it's because I didn't start when I was supposed to. Maybe it's because it's opening night, maybe it's because Hyde Park went so great, maybe its (sic) because I love the show I don't know. But it's safe to say I've never been more nervous before a show in my career, but at the same time I wish today was tomorrow! I can't wait to see you out there," she concluded.
Adele was originally supposed to make her live performance comeback with the residency, but due to the delay, she ended up giving her first public concerts in five years in London's Hyde Park over the summer.
The Weekends with Adele residency is scheduled to run until 25 March 2023.