Wearing a full-length black dress teamed with contrasting red heels and chunky gold jewellery, the 16 year old singer looked classy and glamourous.
The charity event was held in honour of Dee Bee’s Godmother Amy, to raise money for the homeless as well as commemorating her life.
Dionne has been having a pretty good streak when it comes to dress choices, as she looked equally stunning at the Specsavers Spectacle Wearer of the Year Awards last month, and we're especially loving her Angelina-esque leg-flashing red carpet pose!
Dionne was was joined by the likes of Ella Henderson, James Arthur, Tyler James, Mark Ronson as well as other friends and family at The Dorchester last night.
Whilst all the celebs, including Peggy Mitchell! - pulled out their favourite party dresses, we love Dionne's understated, accessorised look.
What do you think?