AceShowbiz - Hilary Duff has tested positive for COVID-19's Delta variant despite being vaccinated. When revealing her diagnosis on social media, the former leading lady of Disney Channel's "Lizzie McGuire" detailed several symptoms that she has experienced.

Making use of Instagram Story on Friday, August 20, the 33-year-old actress shared a selfie of herself. In the accompaniment of the post, she wrote, "That delta … She's a little b***h. symptoms: bad headache. No taste or smell. Sinus pressure. Brain fog. Happy to be vaxxed."

The news arrived just three days after Hilary began filming "How I Met Your Mother" spin-off, "How I Met Your Father". At that time, she shared a photo of her sitting with co-stars Francia Raisa, Chris Lowell, Tom Ainsley, Tien Tran and Suraj Sharma.

In the caption of the post, Hilary penned, "Who's ready for us???" She went on to note, "We may or may not have been sitting in front of a certain someones apartment... #himyf."

Hilary announced her casting back in April. "I've been incredibly lucky in my career to play some wonderful characters and I'm looking forward to taking on the role of Sophie," she said in a statement.

Gushing over the show's creators, the mother of three said, "[Isaac Aptaker] and [Elizabeth Berger] are brilliant, and I can't wait to work alongside them and all of their genius." She continued, "Just fangirling over here... I realize these are big shoes to fill and I'm excited to slip my 6 ½'s in there."

Hilary is not the only celebrity with a breakthrough COVID-19 case. On Thursday, August 19, Melissa Joan Hart divulged in an Instagram video, "I am vaccinated and I got COVID, and it's bad."

"I'm mad, really mad," she further argued. "We took precautions and we cut our exposure by a lot, but we got a little lazy. And I think as a country we got lazy. I'm really mad that my kids didn't have to wear masks at school. I'm pretty sure that's where this came from."