Sarah Hyland - Sarah Hyland Grateful Boyfriend Stayed By Her Side During Health Battle

Hyland and Prokop, who have been dating for two years, play on-screen lovers Hayley and Ethan in the hit U.S. comedy series, but the 21 year old admits their relationship was put to the test when her secret battle with kidney dysplasia came to a head earlier this year (12).

Hyland underwent life-saving transplant surgery this spring (12) and the actress confesses she feared the High School Musical 3: Senior Year star would run from commitment issues - but he stayed right by her side.

She tells Seventeen magazine, "The whole time I was there (in the hospital), Matt was running around and cleaning up the house and making everything spotless, getting air purifiers so the air would be clean and good for me to live in and somehow finding time to see me and spend nights with me in the hospital... Any other 21-year-old guy would not be there, I guarantee it. I am one of the luckiest people in the world to have him be there for me."

And Hyland insists he's offered a great deal of moral support too: "He helps me with my medications and takes me to doctor appointments and all the stuff that I need to do to take care of myself... I used to have to take shots every four weeks, but they were at home. It's a straight-up syringe into your leg. I wasn't able to do that by myself, so he did that for me. Every four weeks, I would freak out and sit in the chair with my pants around my ankles, holding on to a pillow for five minutes being like, 'I'm not ready...' So he knew how to calm me down and make me feel that everything was going to be OK."