Ashley Olsen has reportedly been diagnosed with Lyme disease and has been battling the illness for several years.

A source told American's OK! magazine of the 28-year-old fashion designer and actress, "She's really sick. It's gotten worse. She was diagnosed in the very late stages so early detection measures weren't options for her. She's really going through it."

The debilitating illness can be caused by tick bites and causes joint pain, heart problems and affects the nervous system.

Avril Lavigne recently opened up about her experience with the disease saying, "I felt like I couldn't breathe, I couldn't talk and I couldn't move. I thought I was dying ... I had no idea a bug bite could do this. I was bedridden for five months."