K-Middy joined Pips for drinks and dancing at a friends house near the Middleton estate on Monday evening. "Kate looked incredible," a fellow party animal told People magazine.
"She was very jolly and very happy."
The Duchess, had just come from celebrating Christmas with hubby Prince William, baby George and the rest of the royal clan at Sandringham.
Whereas celebrations at royal Sandringham were super-traditional, formal and very dressy, the party in Bucklebury was apparently relaxed and low-key.
"The thing that really strikes you is that she is just so normal and smiley," the partygoer added. "There are no lights on Kate here, so she can be totally relaxed and herself."