Hear that? It's the sound of more than 1,300 high school students and faculty at Governor Mifflin High School in Shillington, Pennsylvania, sending out a roaring message to the world.

When phys ed teacher Amy Hatlee was diagnosed with esophageal cancer last March, the entire community had (and still has!) her back. To show their support for Hatlee, the school made a very awesome lip dub video to Katy Perry's hit song "Roar." Check it out below:

Mary De Feo, president of Mifflin's Student Government Association (SGA), came up with the lip dub idea while collaborating with the school's longtime SGA advisor, Nancy Brady. De Feo wanted to organize a schoolwide lip dub ever since she saw the nearby Souderton Area High School do one to Sara Bareilles' "Brave."

"We were trying as a student government ... to think of something ... the students could do for Amy to show their support," Brady told MTV News. "I said [to Mary], 'What are we going to do?' So we both went home that night and the next day we had a meeting. I said to Mary, 'Well, what are your ideas?' She looked at me [and] said, 'Well, I think we could do this lip dub' and I looked at her and I said, 'That's exactly what I thought.'"

"I sat down one night and thought about a bunch of songs that had positive vibes," De Feo told MTV News. "I gave the list of the songs to the SGA one meeting and we decided on 'Roar' by Katy Perry."

This vid really hits home for me because I graduated from Mifflin back in 2010, and Mrs. Hatlee taught me during my junior and senior years of high school. As much as I loathed volleyball -- I'm 4'11'', guys, spiking is out of the question -- and running the dreaded mile, Hatlee cheered everyone on as if we were all pro athletes worthy of winning a gold medal. I legit teared up watching this video for the first time.

Hatlee herself is a Mifflin alum, too. She was an elite level gymnast growing up and has competed all over the world as part of the U.S. national team. She's graced the covers of gymnastics magazine covers. After she graduated from high school in 1987, she went on to win the national gymnastics championship while studying at Ithaca college.

She later got married and had two kids -- Hunter, 19, and Trevor, 15 -- and has been teaching phys ed at Mifflin for the past nine years. She's been a gymnastics coach for around 25 years and also coaches the school's track team. I also teared up watching her former gymnasts' heartfelt video to her:

"I have been welcomed back into the Mifflin Community like I never left," Hatlee told MTV News. "I feel like just as much a part of that community as I did when I was a teenager. Governor Mifflin has always had something special to it that I'll never forget, and I can see it just overflowing out the wall of the high school in these past months."

The lip dub is only the latest initiative Mifflin's done for Hatlee. In May, the school held a benefit to help raise money for her medical expenses. Over 800 people -- including students from Mifflin's ultimate rival, Wilson High School -- attended to grab a bite to eat and watch live music performances. Local businesses donated raffle prizes and food for the event. Hamid Chaudry, owner of a nearby Dairy Queen, set up an entire ice cream bar for the evening and gave out "Hatlee Strong" t-shirts in periwinkle blue, the color for esophageal cancer.

(BTW, this all happened after the school already raised over $40,000 in March at their annual mini-THON for the Four Diamonds Fund, an organization fighting pediatric cancer.)

Even though the benefit was a huge success, Mifflin students wanted to do more for their teacher. That's where the "Roar" vid came in. Mifflin junior and videographer Vaughn Golden filmed the lip dub in pretty much one take on Wednesday, June 3. That night, he cut and edited the video and published the final piece to YouTube on Thursday morning. Talk about quick turnaround!

"I think the big thing [is] it was for the most part student-organized and carried out by students," Golden told MTV News. "It may not look as professional as some of the other videos [out there], but the fact that it was carried out by students is something we're proud of."

Let me rewind for a second here. This vid was shot on a Wednesday, a school day, afternoon. That means these kids literally got out of class to put together this amazing thing. How cool is that?!

The school's principal, Mr. Althouse, told us that the students were only in class for the first half of the day. They spent Wednesday afternoon doing run-throughs and rehearsing before the final taping in front of Hatlee.

"It brought the school together in unity," Mr. Althouse said. "It was a perfect opportunity to also support [Hatlee] as well as show our school spirit."

As for Hatlee, she was aware there would be a lip dub, but she had no idea it was going to be for her.

"I knew all year long there was going to be a lip dub," Hatlee explained. "The kids had said, 'Oh, Mrs. Hatlee, we hope you can come back for the lip dub.' ... I was afraid since it was towards the end of my treatment that [it] might be difficult for me, but I happened to be having a great day. ... Everywhere I looked people were holding signs and wearing [Hatlee Strong] shirts and [yelling], 'Mrs. Hatlee, this is for you! This is all for you!' ... It was something special."

Hatlee found out about her cancer on March 24 while at work. The day before she'd undergone an upper endoscopy to check for Celiac's Disease. She had just finished up her school day -- students were still leaving -- when she got the call.

"I knew right when [my doctor] called that it wasn't good news. ... When you hear the words, 'Yes, we found cancer,' it was devastating," she said. "I felt like I nearly passed out. I had to hold onto the wall to get to the [main] office. ... One of my teacher friends, Mrs. [Karen] Redford scooped me up in the hallway and pulled me into the office where the principals just surrounded me and helped me get through those initial minutes."

Hatlee is finishing up her chemotherapy and radiation treatment this week at the University of Pennsylvania. Then, after taking a month or so to recover and gain her strength back, she'll be heading to Boston to have surgery -- what she calls "the big, scary part" -- on her esophagus. Through it all, though, she's maintained a positive attitude.

"With the support I have, how can I be anything but 100% healed?" she said. "I believe that I am going to be healed, and so that's it. That's just it. There's no other option."

She asks her students to only post "100% positive feeling things" on their social media, which they've been doing.

"These kids and faculty members and community -- everyone -- have just stepped up and stepped right in and said, 'Let me take this weight off you' and 'We're going to help you through this,'" Hatlee said. "Like the video says, they're going to help me roar. And let me tell you, they are."