John Stamos has vowed to be by his 'Full House' co-star Dave Coulier's side "through it all", following the actor's cancer diagnosis

John - who plays Jesse Katsopolis in the classic ABC sitcom - wrote on Instagram: "My brother from day 1. Love you @dcoulier and I'll be by your side through it all (sic)".

Dave - who is best known for starring as Joey Gladstone in the show - told this week how he was diagnosed with cancer, after initially visiting the doctors for what he assumed was a common cold.

Speaking to People magazine, the 65-year-old star said: "Three days later, my doctors called me back and they said, 'We wish we had better news for you, but you have non-Hodgkin's lymphoma and it's called B cell and it's very aggressive.

"I went from, I got a little bit of a head cold to I have cancer, and it was pretty overwhelming.

"This has been a really fast roller coaster ride of a journey."

Dave was diagnosed with the form of blood cancer in October after an upper respiratory infection led to swelling in his lymph nodes, and medics immediately conducted PET and CT scans and a biopsy.

He underwent a test to check for cancer cells within his bone marrow and when that came back negative, he admitted it was a "great day" as his chances of survival increased.

He said: "We all kind of put our heads together and said, 'Okay, where are we going?' And they had a very specific plan for how they were going to treat this?

"At that point, [when the test came back negative] my chances of curable went from something low to 90 per cent range. And so that was a great day."