When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. A cancer diagnosis is so difficult. It felt very devastating when Dave called. Dave and [his wife] Melissa called and let us know personally before it went out to the press.

The "Full House" alum revealed Thursday that he wasn't able to shave his head because he's filming a new project soon — and said the criticism "really hurt me."

John Stamos says he was caught off guard by the controversy his bald cap tribute to Dave Coulier has caused on social media. The actor ripped critics who slammed his Instagram post featuring the former “Full House” co-stars just days after Coulier announced he’d been diagnosed with Stage 3 non-Hodgkin lymphoma.

John Stamos shared a post in solidarity with former Full House co-star Dave Coulier — but fans weren't feeling the love.

Now, on Instagram, his “Full House” co-star John Stamos shared images of the lifelong friends together. Stamos was wearing a bald cap and shaving Coulier’s head. “Nothing like throwing on a bald cap and flexing some Photoshop skills to show some love and solidarity with my bro, Dave Coulier,” Stamos wrote.

Dave Coulier, who has an "aggressive" form of Non-Hodgkin lymphoma, said he "laughed out loud" when he saw his "Full House" co-star in a bald cap.

"This one really hurt me mainly because I didn’t understand it," the 'Full House' actor said John Stamos is addressing negativity surrounding his tribute to Dave Coulier. TMZ caught up with the Full House alum,

I’m embarrassed for people that they waste time on this," Stamos said of the backlash. "All I was doing was cheering up a friend."

Dave Coulier and John Stamos have a long history. The two spent years filming the beloved series Full House together, but their friendship did not end there. After the 65-year-old revealed he was diagnosed with stage 3 Non-Hodgkin lymphoma,

Earlier this month, the Full House actor - known for playing Joey Gladstone on the sitcom, revealed he had been diagnosed with a "very aggressive" form of non-Hodgkin lymphoma and was undergoing chemotherapy treatments.

John Stamos defended his actions after facing backlash for wearing a bald cap to show support for fellow “Full House” star Dave Coulier, amid his cancer battle. The internet attacked the famous actor when he shared Instagram posts of himself shaving Coulier’s head,