Bruce Willis' family have gathered around the actor to wish him a very happy 68th birthday.
The Die Hard star looked to be in good spirits as his wife Emma, ex-wife Demi Moore and their children kicked off the classic song.
He even encouraged them to sing a bit louder as they got towards the end.
Emma brought a birthday cake to him and let him blow out the candles to top off the big celebrations.
Demi posted a video of the sweet moment on Instagram and wrote: "Happy birthday, BW! So glad we could celebrate you today. Love you and love our family.
"Thank you to everyone for the love and warm wishes — we all feel them."
Doctors told him in March last year that he had aphasia, which is a disorder that affects how you communicate.
However, the Willis family received the shocking news last month that the 68-year-old also had frontotemporal dementia (known as FTD).
They posted a message onto social media that said: "Our family wanted to start by expressing our deepest gratitude for the incredible outpouring of love, support and wonderful stories we have all received since sharing Bruce’s original diagnosis.
“In the spirit of that, we wanted to give you an update about our beloved husband, father and friend since we now have a deeper understanding of what he is experiencing.
“Since we announced Bruce’s diagnosis of aphasia in spring 2022, Bruce’s condition has progressed and we now have a more specific diagnosis: frontotemporal dementia (known as FTD).
“Unfortunately, challenges with communication are just one symptom of the disease Bruce faces.
"While this is painful, it is a relief to finally have a clear diagnosis.”
Discussing the star’s illness in a further statement, the family added that 'FTD is a cruel disease that many of us have never heard of and can strike anyone'.
Emma Heming Willis posted a video to mark her husband's 68th birthday and reflected on how difficult things have been since the diagnosis was made public.
“So today is my husband's birthday,” she began. “I have started the morning by crying. As you can see by my swollen eyes and snotty nose, I just think it's important you see all sides of this.
“I always get this message or people always tell me like, ‘Oh you're so strong, I don't know how you do it'. I'm not given a choice.
"I wish I was. But I'm also raising two kids in this.”
Heming became teary-eyed when describing that she had created a montage of videos to celebrate her husband’s birthday.
She said: “So I worked on this reel that I'm posting for my husband's birthday. I don't know why I do that because the videos are like a knife in my heart.
"But as much as I do it for myself I do it for you.
“Because I know how much you love my husband and - don't cry Emma - but it means so much to me so thank you.”
Emma received loads of praise for helping her husband and their family navigate through the struggle of dementia.Featured Image Credit: Instagram/Demi Moore