8:18AM, Dec 13, 2006
Some of us need no excuse to get up on stage and flaunt our talents.
And, by the looks of it, Catherine Zeta-Jones was more than happy to give an intimate performance at this private function.
In front of her close family and friends, Cath belted out a little song in honour of her father-in-law's birthday.
But, this was no ordinary birthday - Kirk Douglas was celebrating his 90th with a dinner party at L'Orangerie in LA.
We would love to know what song got Cath so passionate...
... Perhaps she was belting out a number from her Chicago days or maybe she was impersonating Marilyn Monroe's Happy Birthday?
Either way, she proved a good sport and others followed suit.
Check out the fun and celebrations in our gallery above.
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