Vanessa Hudgens is "so proud" of Sarah Hyland for opening up about her battle with kidney failure.

Vanessa Hudgens

Vanessa Hudgens

The 'Modern Family' actress recently revealed she underwent a second kidney transplant two years ago after her first - which saw her father give her his kidney - failed.

And now, Vanessa - who has been friends with Sarah for almost a decade - has praised the 28-year-old actress for being "one of the strongest women" she knows.

The 29-year-old star told People magazine: "I remember when she needed her first transplant and I remember when her body was rejecting it and I remember when she needed her second one.

"I'm so proud of her for being brave to share her story with the world, because it was a very emotional and taxing thing on her. She's just one of the strongest women I know.

"I always will see her as this like tough New Yorker even though she's so petite. She is small but mighty! I'm just really proud of her for sharing her truth."

Sarah revealed this week that she underwent her second surgery after her younger brother Ian was found to be a match and donated his kidney to her, but admitted that the feeling of being a "burden" on her family had left her "contemplating suicide".

She explained: "When a family member gives you a second chance at life, and it fails, it almost feels like it's your fault. It's not.

"But it does. For a long time, I was contemplating suicide, because I didn't want to fail my little brother like I failed my dad... I had gone through [my whole life] of always being a burden, of always having to be looked after, having to be cared for."

And the actress praised her boyfriend Wells Adams - whom she met just three days before undergoing her second surgery - for supporting her throughout her health battle.

She added: "He's seen me at my worst. I think that's why I feel the most beautiful in his eyes, because he still finds me beautiful after seeing all that."