The singer warned one fan, saying: “It landed right by your head. Oh my God, it’s a bat.”
Adele was performing in Mexico City as part of her world tour, which began in Belfast in February.
After a few minutes flapping around, the bat flew away and things returned to business as usual.
It’s not the first time an animal has joined her on stage – and the tour has thrown up some other surprises too.
During a concert in Los Angeles in August, Adele invited a fan onto the stage.
The man had also brought his dog along to see the British singer.
During this round the world trip, it has often seemed that no Adele gig has been complete without a proposal mid-show.
Generally, the happy couple get applause from the audience and a few words from Adele herself.
But if you’re really lucky, like two people in Copenhagen, you get Adele to join in and help you out.
The Grammy award winning singer also picks people from the crowd to join her on stage for a selfie.
It’s not very often Adele is lost for words but back in October the singer was left stumped after a gesture from her boyfriend.
She’s been dating Simon Konecki for five years.
To celebrate the anniversary he replaced her end of show confetti with love messages to the star.
Adele, who before this tour spoke about her nerves when doing big venues, recently announced she’d be playing in Australia for the first time.
She’s also posted a video of her team taking part in the Mannequin Challenge.