And she didn't disappoint, giving us not one, but two style spots in as many days.
Thursday, and the new young mum hit the races looking decidedly svelte in her puff-shoulder LBD.
The 24-year-old showed off her impressive post-baby figure, teaming her Matthew Williamson minidress with towering Louboutin peep-toes, an oversized clutch, heavily-kohled eyes and a slick swinging ponytail.
And after displaying her own style credentials, Coleen then took to the stage to present an award to the most stylish racegoer on the day.
Day two - Ladies' Day - and a more demure Mrs Rooney made an appearance, in a frothy ruffled frock.
Gone was the fierce thigh-grazing mini, to be replaced with a more ladylike calf-length dress - which she informed MC was a fab vintage find that she picked up while on her hen do.
The yummy mummy accessorised outfit two with nude platforms, a matching peachy clutch, gold statement earrings and the same swinging pony.
And as if to mirror the slightly more grown-up look of day two, Coleen also had five-month-old baby Kai in attendance, who sat with his mum to enjoy the day's events.
Two days, two very different looks - but which gets your vote in the style stakes? Let us know your thoughts in the comments box below!