Hilary Duff has tested positive for COVID-19.

Hilary Duff

Hilary Duff

The 'Younger' star has revealed she is currently battling a "bad headache" and is struggling with her taste and smell as well as "brain fog" and "sinus pressure" after being struck down by coronavirus.

Sharing a selfie on Instagram, Hilary - who has had her coronavirus vaccines - wrote alongside it: "That delta [variant] … She’s a little b****. Symptoms: bad headache. No taste or smell. Sinus pressure. Brain fog. Happy to be vaxxed."

Hilary tested positive just as filming started for 'How I Met Your Mother' spin-off series, 'How I Met Your Father', and she previously revealed she jumped at the chance to star in the new show, which has been written by 'This Is Us' showrunners Isaac Aptaker and Elizabeth Berger.

She said: "I’m a fan of Isaac and Elizabeth and was absolutely on board after reading the script for ‘HIMYF'.

"I knew I had to be the one to bring Sophie to life and share the female POV to this legendary show.

"I’m such a fan of the original cast. They were absolutely seamless and brought me many laughs.”

Hilary - who has Luca, nine, with her ex-husband Mike Comrie and Banks, two, and Mae, four months, with her husband Matthew Koma - had previously admitted it was challenging filming her show 'Younger' whilst pregnant amid the coronavirus pandemic.

She explained: "I was a little worried with the challenges of COVID and my pregnancy, but everything came together. I'm all for mask-wearing, but huffing-and-puffing on set in a mask at eight months pregnant was a challenge.

"Fitting into clothes that aren’t made for a pregnant body was not always the most comfortable or fun. And just being freaked out to being exposed to COVID — there are always risks, even though our set was super cautious. I had to quarantine a bunch of times and that was really hard!"