The Texas-born actress looked entirely unruffled by the public display of heartache shared by the younger brother of Backstreet Boys singer Nick Carter as she left a West Hollywood gym accompanied by a male friend.
Dressed in floral-patterned leggings, a black T-shirt and trainers, the 26-year-old looked refreshed and happy with her friend following the workout.
Just the day before, Aaron, also 26, launched an emotional rant on Twitter.
"Don't be that stupid douche that loses the love of your life forever.. Like me..." he posted on Wednesday after user Common Teen shared a snap of the former Lizzie McGuire star, captioning the shot "Hilary duff is flawless".
Aaron didn't stop there and went on to express his need to impress her by proving he’s a changed man. Despite perhaps embarrassing himself online, the ex teenage heartthrob and reality star warned that his comments would continue no matter what feedback he got.
"I'll spend the rest of my life trying to better myself to get back to her. I don't care what ANY of you think,” he added. “That tweet just gave me an anxiety attack.
"Hilary meanwhile, chose not to publicly address Aaron's statements on Twitter, instead telling her 4.2 million followers that she was having a "closet clean out" as she uploaded an image of piles of her clothes on the floor.
The singer-songwriter separated from her husband, NHL player Mike Comrie two months ago. The couple tied the knot in 2010 after three years of dating and welcomed their son Luca into the world in 2012.