Can you believe Donny Osmond is already 60 years old? Neither can the baker who made his cake, apparently.

The singer rang in his 60th birthday on Saturday with a little help from sister Marie and a cake that appears to indicate he’s actually turning 90 years old due to a hilarious mishap.

“Right side up and upside down no matter how I look at his cake…looks like my bro @donnyosmond turns 90 today!” Marie wrote on Twitter with a nostalgic slideshow of photos. “Glad he’s spending this landmark birthday month with his sweet❤️ vacationing!”

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The slideshow features recent photos of the superstar siblings as well as many pictures from over the course of their lives.

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The iconic brother-sister duo opened their show on the Las Vegas Strip back in September 2008, and what was supposed to only be a 6-week run is about to turn into a 10-year streak as their popular show has been extended through the end of next year. The pair, who started as a variety show back in the 1970s, continues to entertain the audiences with both their new and old songs, including hits such as “I’m Leavin’ It (All) Up to You,” “Paper Roses” and “Puppy Love.”

“We’re headed into our 10th year,” Donny Osmond celebrated the news in a press release. “Marie and I are constantly changing our show. That’s probably why we’re fortunate enough to enjoy such longevity.”