The former X Factor contestant looked every inch the fashionista in the thigh-skimming dress that featured embossed tropical blooms, a jagged hemline and a Pater Pan collar.
Because we're fashion magpies, we were pretty certain that we spied this outfit on style savvy Diana's Instagram last week and you'll be pleased to know that you can nab an exact match from Topshop for £65 - hurrah!
A girl after our own heart, Diana took the red carpet by surprise and juxtaposed her feminine ensemble with a pair of smart brogues in a tan hue, propelling flats to the top of the summer style-o-meter.
Never one to follow the crowd when it comes to dressing to impress, Diana ditched the clutch and colour co-ordinated her shoes with an oversized shoulder bag that boasted Western-inspired tassels, buckles and gold chain straps.
When it came to her make-up, the stunner who usually loves the au naturale look opted for a burnt orange lip, a generous dusting of bronzer and lashings of thick black mascara a la Twiggy to offset the retro vibe.
The blonde beauty stood out thanks to her eye-popping ensemble and matching sun-kissed complexion as she mingled with the likes of Matt and Emma Willis on the red carpet before taking her seat inside the London venue.
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