John Stamos Vows to Stand with Dave Coulier 'Through It All' amid Cancer Diagnosis: 'I'll Be By Your Side'

John Stamos is sending Dave Coulier his love following news of his cancer diagnosis.

Coulier, 65, revealed to PEOPLE in an interview published on Wednesday, Nov. 13, that he was diagnosed with stage 3 non-Hodgkin lymphoma in October after an upper respiratory infection caused major swelling in his lymph nodes. 

Hours after the news became public, Stamos, 61, shared a sweet tribute to him on Instagram, filled with various photos chronicling the Full House stars' longstanding friendship.

The post began with a photo of Stamos hugging Coulier and was followed by a throwback photo of the two, seemingly from their days on Full House, which had an eight-season run from 1987 to 1995. Other photos showed the two making silly faces and posing with their late costar, Bob Saget, who died at 65 in January 2022.

"My brother from day 1. Love you @dcoulier and I’ll be by your side through it all," Stamos captioned the post.

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Coulier's wife, Melissa Bring, replied in the comment section, "Love you PP - thank you for the daily support and love!! ❤️❤️"

Fans also commented on Coulier and Stamos' tight bond after working on the beloved sitcom, with one social media user writing, "These relationships that start at work and end up being LIFE LONG friendships are extremely rare.. and quite beautiful. Love the brotherhood between u guys!! 🍻"

Coulier shared with PEOPLE that Stamos would be paying him a visit on Saturday, Nov. 16 — one day after his chemo treatment.

“He goes, ‘If you want to just sleep, I'll just sit by you or if you want to listen to music or just talk, whatever.’ And I'm just like, ‘Wow. That's like a brother. That's just truly a brother,' " said Coulier.

Stamos, along with fellow Full House costars Candace Cameron Bure, Andrea Barber, Jodie Sweetin, Lori Loughlin, Scott Weinger and series creator Jeff Franklin, were all part of a group message that Coulier sent to share the news of his diagnosis.

The actor told PEOPLE that he wanted to make sure that his castmates heard the news from him and noted that everyone's response was "immediate."

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“It was just this outpouring of, ‘I will be there. You just name the time, and I know you're in great hands with Mel, but what can we do?’ It really is overwhelming the love that we have for each other," he said. "We've been there for so many years for each other and it's pretty remarkable."