Mum-of-one Hilary was spotted taking her blonde-haired boy to a children's gym called 'Fit For Kids' in Hollywood and it seems as though they had a great time.
Wearing fluorescent leggings and a grey sweater, the US actress carried Luca on her hip as they made their way inside.
Luca, meanwhile, was dressed in a cute striped vest and shorts, along with blue Nike kicks just like his mummy!
Later, the pair emerged and headed into the sunshine, with Hilary holding her son's little hand as they made their way to the car.
Judging by the looks on their faces, they'd definitely had fun at their class!
The workout with Luca obviously set Hilary up for the day too, as she later tweeted: "Such a pretty day in sunny California! Me so happy :)"
Simon Cowell, EastEnders, Lucy Mecklenburgh: yesterday's headlines in pictures