WATCH: Man SHOCKS family with astonishing 130-pound weight loss!

When 25-year-old Lucas Irwin headed home for the holidays this year, his family had no idea what a huge surprise they were in for. For an entire year before his visitt, Irwin had been determinedly trying to lose weight, without his parents' knowledge. So just imagine their complete and utter shock when their formerly 300-pound son walked in, sporting a newly toned, 170-pound body.

Lucky for us, the big reveal was all caught on video that has since gone viral–and you just HAVE to see the family's reaction. I bet you'll just be as surprised when you see the results  after the jump!

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Irwin had apparently been struggling with his weight for years before he finally decided to buckle down and get fit. By following a strict diet of 1,350 calories a day, keeping track of his food intake through a diary, and walking to work, he managed to lose an astonishing 130 pounds. Wow!

So how did he manage to keep this all from his parents? "I only go home once or twice a year, usually once in the summer, once for Christmas," Irwin told Today. "And I made up an excuse not to go home over the summer just so they wouldn't see me."

I'm sure it must have been really hard for Irwin to go through all of this and not share it with his family. But it was definitely all worth it in the end! As can be seen in the video, the look on his parents' faces when they first lay eyes on their son can only described as pure disbelief. But joyous disbelief!

"All of a sudden, down the stairs he came," his father, Jeff Irwin, told Today. "And he looked just fantastic. I was more stunned than anything else. But inside, I was just beaming."

What an incredible story! I really respect Irwin not only for making the decision to get healthy, but then for doing it all on his own. It can be hard to commit to such a journey, but he clearly knew it would be worth the wait … and it was! He looks fantastic and his family obviously couldn't be more thrilled at all of his accomplishments.

Embedded content: http://www.youtube.com/watch?v=0b4Gve_PaK4#t=27

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