"It really was a great gift," Offerman tells PEOPLE.

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After years of playing fan-favorite Ron Swanson on Parks and Recreation, Nick Offerman says it was time to turn his diet around.

The 46-year-old, who partnered with Lagavulin Single Malt Scotch Whisky to create a special Father’s Day commercial with his dad Ric, says the show’s creators told him not to change his looks when they were filming.

“My boss Mike Schur said the most beautiful thing I think a boss could ever say to a person, which was ‘I’d love for you to stay beefy while you’re playing Ron,'” Offerman tells PEOPLE. “‘Please don’t take the success of the show as an indication that you should start going to the gym,’ and instead to keep it husky.”

“And I said, ‘Thank you so much,'” he says. “It really was a great gift.”

In order to be a “great employee,” Offerman says he ate a lot of high-carb, high-calorie dishes like cheeseburgers and pizza. After the show wrapped in 2015, he says he’s since moved on to healthier options but still has the occasional indulgent meal.

“I’m in my mid-40s and ten years ago I was able to engage in a lot more hedonism in my diet and over the years, I’ve mainly become focused on being healthy. But at our house, my favorite thing to do is grill,” he says. “I love to cook and my favorite way to cook is grilling. Megan and I both, our favorite treat is when I grill burgers. I have my own particular mix of burger ingredients and then bratwurst as well on a grill. Those for me are also the most indulgent times to involve beer and whiskey in my meal.”

The video Offerman created with his dad is part of a YouTube series called My Tales of Whisky. In the ad, Offerman is seen creating a gift for his father in his very own wood shop in L.A. while his father — who Offerman says “steals the show” — is seen almost catching a glimpse of the surprise.

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“I’m glad we’re finally giving my dad some attention. He’s the real star of the family,” Offerman tells POEPLE. “He loves it. Never in a million years did he dream he’d be doing a goofy scotch commercial with me, but my dad is always down for a good time and he takes a very solid swing at it.”

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In honor of Father’s Day, Offerman shared some advice his dad has given him over the years. “My dad kept his lessons very simple. Tell the truth and just be honest with everybody then no one can ever question you, and be polite. He really stressed good manners, opening doors for others and looking around to see who could use a helping hand and always be ready to lend that helping hand.”

He also advised something that came in handy while Offerman was playing the role of Swanson: “If you’re going to do a job, do it right.”