She broke the news on Instagram with a lengthy caption next to three notes pinned to a corkboard reading, "Oct 24," "Adele" and "H.E.R."
"Bloooooody hellllll I’m so excited about this!! And also absolutely terrified!" she wrote.
"My first ever hosting gig and for SNL of all things!!!! I’ve always wanted to do it as a stand alone moment, so that I could roll up my sleeves and fully throw myself into it, but the time has never been right," she added. "But if there was ever a time for any of us to jump head first into the deep end with our eyes closed and hope for the best it’s 2020 right?
"It'll be almost 12 years to the day that I first appeared on the show, during an election ... which went on to break my career in America, so it feels full circle and I just couldn’t possibly say no!"
She gushed about her musical costar, who she admitted to being a big fan of.
"I am besides myself that H.E.R will be the musical guest!! I love her SO much. I can’t wait to melt into a flaming hot mess when she performs, then confuse myself while I laugh my arse off in between it all. See you next week."
Her first appearance on SNL was in 2008, and she then reappeared as a musical guest in 2015.
Fellow celebs and fans were quick to congratulate the "Someone Like You" singer.
“Enjoy the awesome ride!” Gal Gadot commented.
Kate Austin said, "I am absolutely losing my MIND."
"You got this!," Kristofer Buckle said with three hearts.
Meanwhile, her fans are eager for her to drop her new album.
"Until I read the caption it thought this was a new song release," one commented with several crying emojis.
"How many people thought that she was dropping an album called HER on 10/24??" another asked.
Adele's follow-up to 25 was originally due to be released this year but has since been postponed.
"It isn't coming in September, it'll be ready when it's ready," manager Jonathan Dickins said in June. "I can't put a date on that yet. We have music, but we're still working."
In August, Adele admitted that she doesn't know when the record will be out. When a fan on Instagram posed the question, the singer simply said, "I honestly have no idea."
SNL has had to adapt to COVID-19 restrictions but is still going ahead with its 46th season in Studio 8H. The masked audience is reportedly paid to attend the show. The premiere was hosted by Chris Rock with Megan Thee Stallion as a musical guest.
Album or no album, we're happy Adele will be back on the small screen!