KNOXVILLE (WPVI) --CJ and Lucas are best friends.
"Because we both like Star Wars and Nerf guns," CJ Hardy said.
But instead of always pretending to have the force or play war together, the Knoxville, Tennessee boys are having to deal with a pretty adult issue.
Lucas has cancer.
Three weeks ago, CJ shaved his head - because that's what best friends do.
"I wanted to shave my hair because I didn't want Lucas to feel alone if it came back," CJ said.
Lucas was diagnosed with rhabdomyosarcoma in March of this year.
It's a very rare and aggressive cancer that calls for months of treatment and chemo.
But even with all that, unfortunately, he's been given only a 20 to 30 percent survival rate.
"When we're driving and my son says, 'Mom, I found out Lucas has lost his hair and I want to shave my head for him,' it brought tears to my eyes," CJ's mom Jessica Hardy said.
So far, support has been wonderful, but bills are starting to add up and so is the stress.
So Lucas' best friend is trying to help.
CJ is holding a fundraiser with a bounce house, silent auction and a sponsored kick-a-thon with all the proceeds going to Lucas' family.
"With Lucas he understands this is very serious for him and I think this is what motivates him even more to push forward and try to help him," Jessica said.