Over the weekend, the Hemsworths all posted gushing posts about their mum, Leonie, to their social media accounts.
"Happy 60th to the greatest mum on earth! Love ya, mum," the 37-year-old wrote alongside a few snaps of himself and Leonie from the birthday bash.
The Thor actor left his fans gobsmacked with some suggesting she looks more like his sister than his mum.
"Your mum is 60?!! Wow she looks great!" one fan wrote, while another added, "60? Lord she looks younger happy birthday."
"Wait what?! She 60?? She look so damn young!!!" one shocked fan said.
Another got Leonie confused with Chris' wife Elsa Pataky, writing: "I thought she was your girlfriend."
Someone else wrote: "No way your mum is 60! She looks younger than me and I’m 44. Wow! Beautiful. Clearly she passed on the good genes. Glad you all are having fun."
Elsa has previously spoken about the key to Leonie's good looks, saying her secret is that she's "strict" about intermittent fasting.
Intermittent fasting involves increasing the time between your final meal from the night before to when you start eating the following day. The most common type of intermittent fasting sees people fast for 16 hours and eat within an eight hour window, which might be from 12pm to 8pm.
"The first person we knew who started [intermittent fasting] really strict was Chris' mum, actually," Elsa told Body + Soul in May.
"She just looks amazing! She's 60 almost, 59, and every year looks even better... She started with one day of fasting, once a week, and then she started with the 15-16 hours of fasting."
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