John Stamos is on the receiving end of backlash after wearing a bald cap in an effort to show solidarity with friend Dave Coulier, who is undergoing cancer treatment.

The 61-year-old actor — who starred on the beloved 90s sitcom Full House alongside Coulier, 65 — took to Instagram on Monday to share a set of pH๏τos with Dave in a joint post.

John wrote in the caption, ‘Nothing like throwing on a bald cap and flexing some PH๏τoshop skills to show some love and solidarity with my bro @dcoulier.’

He praised his longtime buddy for handling his stage 3 lymphoma battle with ‘so much strength and positivity.’

Some fans took offense to the gesture, with one person writing in the comments: ‘I’m sorry as a breast cancer survivor this is not support. This is a joke. You should be ashamed of yourself. That’s not how you support us.’

Another slammed him, posting, ‘Why the bald cap! You could’ve supported your friend without “pretending” to shave your head!! If my friend did this to me I would be so offended!! I mean look at me with my fake bald head that I can take off whenever I want.’

John Stamos is on the receiving end of backlash after wearing a bald cap in an effort to show solidarity with friend Dave Coulier, who is undergoing cancer treatment

The 61-year-old actor – who starred on the beloved 90s sitcom Full House alongside Coulier, 65 – took to Instagram on Monday to share a set of pH๏τos with Dave in a joint post

There was also a note that stated, ‘That’s not solidarity. You didn’t actually shave your head. Wow… you should have just posted you are there for him without the insult.’

‘Come on John shave it!!! Sending much love and strength,’ one social media user added to the discourse.

Meanwhile, someone else reasoned, ‘I think some people might not understand that he probably cannot shave his actual hair because he might be under contract for a show or a movie.

‘But it doesn’t even matter the fact that he’s by his side during this tough time should be the only thing that matters. Sending prayers for healing.’

Stamos continued in his caption, ‘I know you’re going to get through this, and I’m proud to stand with you every step of the way. I love you.’

He also gave a shoutout to Dave’s wife Melissa, penning, ‘(p.s. – @melissacoulier is the most wonderfulest – your true life line!).’

One of his followers shared a lighthearted perspective, posting in the comments, ‘Wow. After reading all these comments, if I ever lose my hair NOBODY better shave their damn head to “show” they support me.

‘Please use a bald cap if you want to make me laugh lol.’

Some fans took offense to the gesture, with one person writing in the comments: ‘I’m sorry as a breast cancer survivor this is not support’

Another slammed him, posting, ‘Why the bald cap! You could’ve supported your friend without “pretending” to shave your head!!’

As John tries to be a supportive friend to Dave, he’s also mourning the loss of his childhood friend Mike.

In a vulnerable post earlier in the day, he shared a series of old pH๏τos and added a heartfelt, candid caption.

The lengthy message began, ‘On a flight to Detroit to visit my friend Dave, I got a text from my best friend’s brother: “Call me.” My stomach dropped. “Is Mike OK?” I sent back. The response took forever, those cruel three dots hovering on my screen. Finally, just two letters: “No.”’

He went on to share, ‘Mike Owen, my best friend since I was 11, was gone. A sudden heart attack. Just like that. The world I’d built around our friendship shifted, surreal and devastating.

‘Mike wasn’t just my friend. He was the friend. My everything friend. From the moment we met, we were inseparable, two boys finding magic in Disneyland and in each other’s company.’

He remembered fondly, ‘He was the guy who always let me shine, always happy to be in the shadows, cheering me on. Mike had this way of making the world feel steady. He wasn’t flashy, didn’t need to be the center of attention, didn’t hunger for more than what he had. His gift was something most people spend their lives chasing: contentment. It wasn’t complacency. It was peace.’

John’s tribute continued: ‘Mike carried our shared history with a reverence I didn’t always understand. Now, I think he knew something I didn’t: how fleeting life is. He held onto our memories not to live in the past, but to savor the beauty of our bond.’

John opened up to his 4.3 million followers, ‘Three weeks ago, Mike gave me one last gift. I flew him to Disney World, and we spent days like we were kids again—laughing, reminiscing, doing old bits, sitting on familiar benches, soaking in the magic of our friendship. It was pure joy, and I’ll treasure it forever.

‘Losing Mike feels like losing a piece of myself, like chapters of my story are missing now. He knew every secret, every joy, every heartbreak.

‘But I know what he’d want: for me to hold onto the love and laughter we shared and to remind you—don’t wait. Say the thing. Book the flight. Tell the people you love how much they mean to you, today!’

Lastly, he said, ‘Mike, I’ll miss you every day. You were my brother, my compᴀss, my greatest friend. You taught me to find joy in simplicity, to laugh through life’s hardest moments, and to treasure what we have while we have it. I love you. Always. Rest easy, my friend.’