'Pawn Stars' Corey Harrison Calls Grandfather Richard Harrison His 'Best Friend'

Corey Harrison, the grandson of Richard "The Old Man" Harrison featured on History Channel's Pawn Stars, took to social media to mourn his grandfather's passing Monday morning.

"I was lucky enough to spend 15 years of my life working with the old man. He wasn't just a grandfather, he was truly a best friend as well," Harrison wrote alongside a throwback photo of Richard. "I'm truly blessed to have had him as a mentor. He will be missed everyday at this time we thank you for all of the kind words and we ask for privacy as we mourn his passing."

The "Old Man" died Monday morning from Parkinson's disease, his son and Harrison's father, Rick Harrison, announced. He was 77.

Rick remembered his father with an old headshot of him from his Navy days.

"Today I lost a friend, a father, a teacher and so much more. The Old Man lost his long battle with Parkinson's this morning. Love you Dad. See you on the other side," Rick wrote Monday after initially announcing the loss of the "Old Man."

"Richard Benjamin 'The Old Man' Harrison passed away this morning surrounded by those he loved. He will be tremendously missed by our family, the team at Gold & Silver Pawn and his many fans the world over," Rick wrote earlier in the day on Instagram, as previously reported.

Rick continued, "He was my hero and I was fortunate to get a very cool 'Old Man' as my dad. That I got to share him with so many others and they got to see what a great family man he was is something I am grateful to have experienced with him."

"He lived a very full life and through the History television show 'Pawn Stars' touched the lives of people all over, teaching them the value of loving your family, hard work and humor. We appreciate everyone's thoughts and prayers and ask that we are provided some privacy at this time," he concluded his initial post.

Richard shot to reality TV fame when the History Channel featured his Las Vegas pawn shop that he owned with son Rick, Gold & Silver Pawn, on its series Pawn Stars in 2009. The "Old Man" was a fan favorite cast member on the long-running series, which recently aired its 500th episode. Fans knew the "Old Man" as the grumpy, yet lovable, head of the business.