Opting for a black, gypsy-style bardot with a pretty tie at the neckline, the singer left her gold hair loose and let the top do the talking.
Pairing it with a matching skirt with zip detail and some gorgeous black heels, Ellie was picture perfect for her dinner date on Thursday (22 September).
The singer headed to luxe restaurant China Tang with her royal pals Princesses Beatrice and Eugenie, as well as Bea's mum Sarah Ferguson, following her gig in Marylebone.
After feasting on the lavish menu, the girls left together and Ellie clutched a matt black bag which coordinated perfectly with her all-noir get-up.
Princess Bea isn't the only royal Ellie is close with. In fact, rumours have been swirling for some time that the singer may well be dating Prince Harry!
Nothing has been confirmed, though Harry and Ellie have been friends since she performed at his older bro William's wedding to Kate Middleton in 2011. And after they hung out together at a polo match earlier this year, some have suggested that they might be an item.
Either way, Ellie split from long-term boyfriend Dougie Poynter back in February and she's been super busy ever since.
As well as promoting her new single for Bridget Jones's Baby, Still Falling For You, Ellie's released her album Equilibrium, has been enjoying a hectic gig schedule this summer and she's also the face of haircare range Pantene's Strong Is Beautiful campaign.
You can totally tell from these snaps that Ellie's hair is on point right now.
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