Meet Sammie and James "Jimbo" McComb, a daughter and dad living in Thousand Oaks, California.
But, it turned out he made a big mistake: It was a 60th birthday party — not a '60s-themed party.
"I guess he just misread the invitation because it said ‘the big 60,’ or something like that," Sammie said.
Sammie shared the hilarious photo on Twitter, where thousands of people have been cracking up over it.
It's just so, so good.
And this isn't the first shenanigan he's gotten into. One year, he gave Sammie a framed, autographed photo of himself for Christmas.
Which is basically the daddest thing that has ever happened.
Sammie said the whole costume mishap was "the funniest thing," but not as surprising as you might expect.
"It was just so like my dad," she said. "He does this stuff all the time."