Coulier, who rose to fame alongside Saget on the ABC sitcom "Full House" in 1987, actually met the late actor years before when the two were struggling stand-up comedians.
Coulier, 62, honored his friendship with Saget, who was found dead at age 65 in a Florida hotel room on Sunday, by sharing a collection of throwback photos of the pair Thursday on Instagram. In one hilarious snap, the two funnymen pose beside each other wearing women's bustiers. In another, they're seen relaxing on a golf cart.
Coulier also included an image of a ticket stub from a 1992 comedy show the pair co-headlined together.
"I met Bob when I was 18 years old. I didn’t know then that two, struggling standup comics would end up being brothers forever. I wish I could lean on you right now through all these tears. I love you," he wrote in his caption.
Saget's widow, "Eat Travel Rock" host Kelly Rizzo, commented on Coulier's post to tell him how much her late husband adored him.
"Dave. Bob said CONSTANTLY, 'No one in my life makes me laugh harder than Dave.' He must’ve told me 10 Dave stories everyday for 6 years. Cannot wait to hug you. I love you," wrote Rizzo.
Shortly after the media began reporting about Saget's death on Sunday, Coulier posted a photo of himself holding hands with Saget.
“I’ll never let go, brother. Love you,” he wrote in his caption.
A day later, the original cast of "Full House" shared a collective statement honoring Saget's memory on Instagram. "Thirty-five years ago, we came together as a TV family, but we became a real family. And now we grieve as a family,” read the statement, which was signed by Coulier, Candace Cameron Bure, John Stamos and their co-stars.
The tribute went on to remember "our sweet, kind, hilarious, cherished Bob" for both his humor and his kindness. It also mentioned that Saget was famous for giving good hugs.
On Thursday, Bure celebrated the memory of Saget's warm hugs again when she tucked several images of Saget hugging his "Full House" family members into her Instagram stories.
"Always hugs. Always," she wrote, adding a happy emoji.