ABC News' Sabrina Parise reports:
To an outside eye, Frehley Gilmore looks like a typical 10-year-old girl.
The Menasha, Wisc., native is the catcher on her softball team, loves hanging out with her friends and has a pet guinea pig named Toby.
"She has so many good qualities," her mom, Lisa Gilmore, told " Good Morning America." "She's the one friend that will give the hug when the other friends are being mean."
Those qualities did not change last February when Frehley received a life-changing diagnosis. After complaining of headaches and stomachaches, doctors found a tumor in her brain and diagnosed her with stage 3-4 cancer.
"She's been totally normal since birth until last year…we had never had her in the hospital, ever," Gilmore said. "And then it all began, our whirlwind, our ups and downs."
Two days after doctors found the tumor in her brain, Frehley underwent surgery to have it removed. The surgery was a success and, now, nearly nine months later, Frehley is cancer free.
"She's amazing," her mom said. "She's just like a little rock and that's what kept us all together."
Like any 10-year-old girl, Frehley is a huge fan of pop superstar Selena Gomez. So when Make-a-Wish, an organization that grants wishes for children with life-threatening illnesses, asked what her wish was, she did not hesitate in her reply.
"I wish to meet Selena Gomez 'cause she's awesome," she said.
Make-A-Wish, which is once again this year partnering with Macy's for the annual "Believe" campaign to raise money and deliver kids' letters to Santa, let Gomez know of Frehley's wish and the star jumped at the chance to meet the young girl.
"GMA" was there to capture it all.
Frehley and her family traveled from Wisconsin to New York City for what Frehley thought was a chance to talk about Make-A-Wish. As the family sat with "GMA" news anchor Josh Elliott over frozen hot chocolate at New York's famed Serendipity restaurant, the young girl got the surprise of her life.
Into the restaurant walked Gomez, who said the restaurant, which Frehley will always now remember as the place her dream came true, holds a special place in her heart too.
"You know, me and my mom make a tradition every time we come to New York, which is a lot for my job, we always used to come here together, so it was my mom and daughter place," Gomez said.
The "Wizards of Waverly Place" star, who has performed in front of millions of people, walked red carpets and appeared at countless award shows, also told Elliott that this, making fans' dreams come true, is one of the things she loves most about her high-profile occupation.
"It's probably one of my favorite things that I do for my job," she said. "It makes me happy to come out and do this. I feel like I'm not doing enough."
HOW YOU CAN GET INVOLVED: Bring a stamped letter, addressed to "Santa At The North Pole," to your local Macy's store and drop it in a special Santa Mail letterbox. For each letter received through Dec. 24, Macy's will donate $1, up to $1 million, to Make-A-Wish. Macy's will count up the letters and deliver them to the Post Office.
Click here to locate a letterbox near you.
For more information on the Believe campaign, go to Macys.com/Believe.