A high school senior who has been battling a rare type of cancer recently married his girlfriend after doctors delivered a heartbreaking prognosis.

Chase Smith and Sadie Mills tied the knot on April 29, just days after he was told he had three to five months to live because of his battle with Ewing's sarcoma, The Indy Star reported.

The couple, who started dating six months earlier, celebrated their nuptials on Mills' parents' Indiana driveway in the exact spot where they shared their first kiss, according to the outlet.

"Overall, it was the best day of my life," Mills said in a video interview. "I've always wanted an outdoor wedding and the fact that Chase came up with the idea to have the altar right where we went on our first date, where we had our first kiss, that meant a lot to me."

The 18-year-olds' wedding was something they had dreamed about for quite a while, explained Smith, who has been battling the rare form of cancer since he was 12, according to The Indy Star.

Their plan was to graduate high school, attend college together (where they hoped to continue their swimming and diving careers), and then eventually tie the knot, the outlet reported.

However, a wrench was thrown in their plans when Smith went to the doctors in March and learned that his cancer — which typically occurs in bones or in the soft tissue around the bones, according to the Mayo Clinic — had returned.

With tumors all over his body — including his skull, the fluid lining of his brain, his shoulder, lung and hip, according to The Indy Star — doctors broke the heartbreaking news that, with or without treatment, his prognosis did not look good.

After learning that devastating information, the couple knew what they wanted to do.

"We definitely were thinking about getting married in the future and we knew we wanted to," Smith explained in a video interview. "A lot of people do say, 'Oh they're getting married because he has a potential to pass away soon,' and that's not at all why we decided to get married. It was more of just a wake-up call that, 'Hey, God wants you two together.'"

"What was cool about that was whenever we were first talking about getting married, Chase brought it up and I already knew what he was gonna say," Mills added. "So I interrupted him and said, 'No, I know the same thing.' So that was definitely a God thing that the time was right."

Within four days, the pair spoke to their parents and then managed to plan a wedding in Mills' front yard — thanks in part to what Smith called their "alpha dog" sisters' organization and their parents' support.

"I have the best two parents I could possibly have. For them to be a hundred percent behind me and my choices and my decisions on who I love and who I wanted to marry when I wanted to marry, it couldn't mean any more to me than what it did," Smith said.

On their big day, Mills wore an elegant white gown as she walked towards her groom in his navy suit at the front of the altar. Smith recalled how he was overcome with emotion in that special moment.

"I was so excited to see her 'cause I hadn't seen her all day," Smith explained of why he broke down in tears. "It was the pure reaction of being able to see her... It was like a hit in the chest of emotion."

With an unknown future ahead of them, the newlyweds said they're relying on their faith and each other to keep them moving forward.

"That's 110% due to the trust in God," said Smith, who has a GoFundMe page set up on his behalf to assist with medical expenses. "With God, I always know I have a shot. As long as he's by my side, I always have the strength to do whatever."

Of his new wife, Smith added: "She calms my fears... when I'm having rough times with my diagnosis or I'm in pain or in high anxiety times, she's the one person that I can go to and she can get my heart rate down, get me to relax, get me to think of something else."

"We're able to have that natural connection of being able to talk and be able to calm each other down in those scenarios," Smith continued. "It's been the best month of my life, for sure."