Addison Kleinhans is 7 years old. His best friend, Bella Hicks, is two years younger. But despite their gender and age differences, they call each other soul mates, or BFFs. They are together all the time, because they are battling the same disease, together.

Both suffer from acute lymphoblastic leukemia, a type of cancer in the white blood cells. But what's even more telling is they were diagnosed one day apart. They are still undergoing chemotherapy to beat cancer.

Here's their story:

Bella has the best line: "I can't wait to be done with cancer."