"The language I used was unacceptable," she told her Instagram followers.
The Hold My Hand singer has sparked controversy following an appearance on Mo Gilligan's podcast.
Mariah's All I Want For Christmas Is You topped the UK charts for the first time in 26 years this month.
Jess Glynne Addresses Restaurant 'Discrimination' Post After Facing Backlash: 'It Wasn't The Right Word'
The singer claimed the intention behind her divisive Instagram comment was so the Sexy Fish restaurant staff could "better themselves".
Jess Glynne's Claim She Was 'Discriminated' Against Because Of Her Casual Clothes Has Not Gone Down Well
The Hold My Hand singer has said she was turned away from a fancy London restaurant because she was wearing a hoodie, baseball cap and trainers.
The chart-topping singer has said she has "unfinished business" with the festival.
Hanson, Amanda Holden and Jess Glynne are also among those who have popped up in Erinsborough over the last 37 years.
The singer has knocked Adele off the top of Heat magazine's Rich List.
She also confirmed she partied with the Spice Girls the night before she was due on stage at the Isle Of Wight festival.
The I'll Be There singer had been scheduled to appear at the Isle Of Wight the night after her final performance on the Spice World 2019 tour.