Kelly Osbourne has been battling a 100.2-degree fever.

The former reality TV star, 40, who has one-year-old son Sidney with her musician boyfriend Sid Wilson, complained to fans she can't find any remedy to work as she fights her festive illness.

She said on her Instagram Story while revealing the level of her fever: "Still going strong. I have put ice on my body, taken meds, tried to sweat it out in the bath and nothing is working!"

In another video, she added: "Day three of having a fever and a little cough. "Babies bounce back so quickly but I don't seem to be at all. I don't want to be sick anymore."

Kelly then revealed she had taken her little boy to the doctor and learned there that they are both sick with respiratory syncytial virus.

Known as RSV, it's is a common illness that causes infections of the lungs and respiratory tract.

It's especially common in winter and infects most children by the age of two.

Kelly and her toddler have been sick together before - with the pair both battling flu in 2023.

Her partner Sidney, 47, who is the DJ for metal band Slipknot, also recently had a health scare when he suffered severe burns following an explosion at his and and Kelly's farm in August.

Kelly rushed with the musician and their son to the emergency room and later warned her followers: "This is why you don't f*** with burn piles."

Sid - who shared videos of Kelly treating his burned face with cream in the wake of the accident - opened up about the ordeal days later.

He told fans his face had been "basically melted from the nose down".

Sid added to Fox News Digital: "My whole right arm is bandaged up, half of my left arm.

"But the swelling's gone down, and they said the face is kind of amazing that it's regenerative, it happens real fast, seems to heal quickly."