Country cutie Kellie Pickler has a big voice ... but an even bigger heart.

The former American Idol contestant stopped by The Ellen DeGeneres Show to discuss shaving her head in support of her BFF Summer who was diagnosed in June with breast cancer.

Kellie tells Ellen:

    "We made a pact that we would shave our heads together. I think last thing that you want (for) anyone that you love to feel like… is that you don’t want them to walk through the valley alone. I think it’s important to have a cancer buddy."

As for the moment she shaved off all her blonde hair, she adds:

    "That is probably one of the most beautiful moments of my life. Just being able to do that with her.

We think Kellie is beautiful both inside and out.