Deciding on a prom date can often be a stressful time for any high school senior, but Shelby Butler quickly decided that she had a special someone in mind.

"This was the easiest choice I made all year,'' Butler told TODAY.com.

Georgia high school senior Shelby Butler made a special promposal to family friend Alex Richards, 8, to ask him to her senior prom. Courtesy of Shelby Butler

The senior from Apalachee High School in Winder, Georgia, made a special promposal on Sunday to family friend Alex Richards, 8, who is battling cancer for the third time in his young life. She made a series of poster boards to surprise the boy she calls her "superhero," and he happily said yes.

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"Superman is cool because he has X-ray vision,'' she wrote on the poster board. "Superman is cool because he scales tall buildings. Batman is cool because he drives the fanciest car on the planet. Alex is cool because he never stops fighting. I would like my superhero Alex to be my date to the prom."

Butler made up a special posterboard for her 'superhero' Alex, asking him to the prom. Courtesy of Shelby Butler

"It was really heartwarming for me because he goes through so much,'' Alex's mother, Sheri Richards, told TODAY.com. "In my eyes I'm seeing it as her giving up her senior prom and being with her friends, but she's making sure he has a good time and getting away from the hospital for a little while to have fun."

Alex, who was initially diagnosed with T-cell leukemia when he was 4 years old, has already undergone multiple chemotherapy treatments and a bone marrow transplant in his young life. In March 2015, the cancer came back for a third time, necessitating more chemotherapy treatments, which he recently finished.

The two shared a hug after Alex checked the box saying 'yes' to Butler's promposal. Courtesy of Shelby Butler

"He just never stops fighting,'' Butler said. "I thought of a million things, but I remembered when he gets his chemo, we call it his superpower, so that's where I got the superhero (theme) from."

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Butler has been close with the Richards family, including Alex's older sister Julia Richards, 19, for her entire life. Julia Richards, a freshman at Georgia State University, was the donor for Alex's first bone marrow transplant. If he goes into remission from the latest round of chemotherapy, she is planning to donate again for a second transplant.

Butler is working on trying to get a limousine for the big day on April 9 at the Georgia Center in Athens. Alex already has a blue suit to match her blue dress, and the two plan on hitting Steak 'n Shake before the prom.

Butler also got Alex a box of Legos as part of her promposal. Courtesy of Shelby Butler

"I just wanted him to be able to have a fun night and dance and have a good time,'' Butler said. "He's stuck inside a lot for his treatments, so I just wanted him to get out for a little while and enjoy himself."

"He is excited about it,'' Sheri Richards said. "Shelby is just the most selfless kid, and I think years from now it will really hit him about what she did for him."

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