The beauty, who plays teenager Haley Dunphy in the hit U.S. comedy, was just nine years old when she was diagnosed with kidney dysplasia, a disease which causes abnormal organ development and often requires a lifetime of dialysis treatment.
The 21 year old has been quietly struggling with the disorder ever since but after landing a role on the Emmy Award-winning series, her health severely deteriorated.
During an appearance on U.S. breakfast show Good Morning America on Monday (14May12), she said, "I was in pain a lot of the time. If I didn't get 12 hours of sleep I felt like I got none at all."
Hyland tried to keep her problems under wraps to avoid disrupting the rest of the cast and crew but earlier this year (12), the TV star found a match in her hunt for a donor - her actor dad Edward James Hyland.
She subsequently underwent transplant surgery in April (12) and she's now planning a restful summer of recovery while her show is on hiatus - and she decided to speak out about her health issues to encourage young fans facing similar problems.
Hylands added, "Know that you're not alone, even though it may seem like it a lot of the time. And if you ask, 'Why me?' Well why not you? It makes yourself the person you are today."