Man with Down Syndrome Performs ‘Chasing Cars’: He 'Makes Me Smile', Music Teacher Says

A music teacher from New Zealand is helping to bring a smile to people with special needs, one chord at a time.

Robert Mullen — who has worked with people with special needs for nearly two decades — has always been fascinated by music and its ability to “unlock hidden treasures within people.” After taking a two-year break to learn how to play the guitar and other instruments, Mullen is incorporating music into his program that helps those with special needs.

“When it comes to teaching and mentoring,” Mullen, 41, tells PEOPLE, “my approach is to see what is inside someone and use whatever means or technique to be able to bring it out and help them shine.”

Mullen regularly posts videos of his music sessions to Facebook, and one heartwarming video featuring a student named Alex who has Down syndrome has garnered much attention over social media, as first covered by CBS News.

“Alex is a real joy to work with. He is 27 years old and has Down syndrome. However his ability is far greater than his disability,” Mullen says. “He has a passion for music and performing. Mentoring Alex is a blessing and so rewarding seeing both the smile on his face and the progress he is making in developing and fine-tuning his talents.”

The video shows Mullen pulling out his guitar to jam to Snow Patrol’s 2006 hit, “Chasing Cars,” as Alex plays along on his harmonica.

“The video was spur of the moment, we had just finished a lesson were about to pack up and I just started playing the guitar part and singing to myself when Alex joined in,” Mullen recalls.

“I instantly stopped and set the camera up to record and what came out is what you see now,” he continues. “It was just one of those special moments.”

In the video, a delighted Alex gently plays his harmonica and sings along with Mullen. But after finishing the beginning of the song, Alex puts down his instrument and breaks into his own rap — making the song all his own.

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The video has earned more than 16,000 views on Facebook since being uploaded on October 30, and many commenters praised Alex’s talents. Now, Mullen says, they are being asked to cover “Chasing Cars” and other songs at events around their community.

With the added attention, Mullen says he is now inspired to look for a larger studio in the coming year to further allow his students to express themselves artistically.

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“Even though I am qualified to teach music, I call myself a mentor rather than a teacher,” Mullen says.

“I currently I have four students and a few more lined up for next year. I am working more with people with learning disabilities, or who have low self-esteem, and using music and creativity to help them both express themselves and grow within their personal development.”

It’s the reaction from his students, such as Alex, that makes it all worthwhile.

“Seeing the joy on [their] faces always makes me smile,” Mullen says, “and brings me joy.”