Instead, the bikini model chose to celebrate her milestone birthday in the company of her uncle, Congressman Fred Upton (who is the Republican representative for Michigan in the US) and his friend, Republican congressman Kevin McCarthy.
A fresh-faced Kate posed for a picture with the two gentlemen, with Rep. McCarthy posting the happy snap to his Instagram account.
The photo showed a smiling Kate in a simple black dress with the two men donning suits for the occasion and was captioned: "With Congressman Fred Upton and his niece, Kate. We are celebrating Kate's .21st Birthday #kateupton". Talk about party animals.
While one would be forgiven for thinking the kind of 21st party we're accustomed to seeing from other stars, the evidence of it is yet to appear.
A few 21st birthday salutations appeared in Kate's twitter feed, including a 'thank you' Tweet to her family and friends, as well as a few retweeted photos of friends, but nothing else yet.
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