Brad Paisley is one of many country stars deeply mourning the loss of an icon in their trade, Glen Campbell. In Billboard and on social media, Paisley recounts his earliest years in music, and how Campbell was a model and mentor for him.

"Glen was the first of his kind in [the country] format, which was guitar player, personality and singer," Paisley writes. "He’d sing, he’d play the fire out of the guitar, he’d tell a joke, and then he’d be back to singing. It was like, 'Okay, that’s what I want to do.'"

While opening for the legendary singer as a teenager, Paisley says he learned about more than music from Campbell: He learned how to entertain people from stage with grace and ease.

"It was interesting because a lot of his records didn’t have a lot of guitar on them. Every now and then there would be and the guitar parts were iconic and classic, but understated," Paisley notes. "It was live where he threw out the rulebook and used it as another way to reach the audience."

In 2011, Paisley was tapped to help honor Campbell at the CMA Awards, shortly after Campbell revealed his Alzheimer's diagnosis. Accompanied by Jimmy Webb, Paisley, Vince Gill and Keith Urban ran through some of Campbell's biggest hits.

"We were products of the path that he forged. He’s a Mount Rushmore-type act for us," Paisley reflects. "There was a time when he would have been anyone’s gateway drug into our format."

After Campbell's death on Tuesday (Aug. 8), Paisley also posted on Twitter, commending Campbell's "artistry, grace and class" and calling him "a shining light." On Instagram, Paisley reflected on the need to find a cure for Alzheimer's disease.

"Alzheimer's is a thief. And although it may rob someone of their memories, it cannot touch their legacy. And what a legacy you leave behind Mr. Campbell," Paisley writes. "Let's figure this disease out once and for all. In memory of Glen."

In November, Paisley's mother-in-law died following her own battle with dementia.

Country Artists Pay Tribute to Glen Campbell