"We've lost one of our own now to this silent enemy," Strait wrote on social media. "That really hit home to me. I worked with Joe in the past. Great guy and hugely talented singer and entertainer."
Diffie, the Oklahoma-born hit-maker behind "Pickup Man," "John Deere Green," "Bigger Than The Beatles," "Third Rock From The Sun" and other '90's classics passed away on May 29, just two days after it was announced that he'd contracted COVID-19.
The Grand Ole Opry member for 25 years strong (and Grammy award winner) lived the full creative cycle of a veteran country singer, including a stint with a Highwaymen/Old Dogs style supergroup with Sammy Kershaw and Aaron Tippin.
Based on the outpouring of tributes, Diffie earned the adoration of his forerunners (Strait, Steve Wariner and Charlie Daniels), peers (Trisha Yearwood, Travis Tritt and Tim McGraw) and younger country stars (Brad Paisley, Jason Aldean, Cole Swindell and Chris Young).
Strait closed his short tribute with words of hope in troubling times.
"Let's pray for his family and for all those who are affected by this terrible virus," he wrote. "We are going to win. Please stay home, healthy and well. Pray for your family, friends, first responders, health care providers, our President and the world."
In recent weeks, the coronavirus pandemic has impacted every country music singer reliant on live gigs to make a living.
Other country artists to contract COVID-19 include actor and singer Laura Bell Bundy and "Fight Like a Girl" singer and songwriter Kalie Shorr. It's also caused an ongoing health scare for Americana legend John Prine, whose wife Fiona has reportedly recovered from the virus.