With only four days to go until Kate Middleton turns 30, her sister Pippa and brother-in-law Prince Harry, have become planning for a birthday party in a secret location in London that will only be open to close friends and family, the Daily Mail reported.

As far as rumors go, the Duchess of Cambridge will be celebrating her 30th birthday with cocktails and Karaoke in an eighties theme party, a royal source told Grazia magazine.

Prince William will be taking Middleton to the premiere of Stephen Spielberg's film War Horse on the eve of her birthday on Jan.9. The couple is expected to attend a   £10,000 a ticket charity dinner afterwards, the Daily Mail reported.

In many ways, this is going to be Kate's last chance to let go like she did back in the old days when she and William first met, a Royal Source told Grazia.  

The insider told Grazia magazine that Prince Harry and Pippa Middleton have been organizing the party for months with the help of close friends.  Guests have apparently been told to save the date but have not been give the secret location yet. All that has been revealed is that the party will be held in London.

Rumors have been spreading that the Queen will give Middleton a tiara for her birthday from her special collection.

The Duchess' birthday outfit is another secret that is being well kept. Middleton dazzled at her first royal Christmas dressed in a plum-colored fitted coat complete with a magenta hat and gold drop earrings. She was revered as one of the greatest fashion icons of 2011.

One part of her outfit that really stood out next to her Jane Corbett magenta hat, were her 18ct gold drop earrings. According to the Daily Mail the gold -drop precious- stone earrings are made by Chelsea-based Kiki McDonough, and worth £1,900. The biggest rumor on the Royal mill is that they came as a Christmas present from her husband, Prince William.

Middleton has been spotted wearing other kinds of Kiki Jewelry this year, including: a small silver diamond-studded cross on chain and matching diamond earrings, the Daily Mail reported. She has also been seen in a pair of 18ct Citrine drop earrings valued at £495.

Since marrying Prince William in a Sarah Burton for Alexander McQueen dress, Middleton has been heralded for her sense of style. In visits to charity organizations the media as much, if not more, closely than the visits themselves has covered the duchess' outfits. Her wardrobe has been followed so closely that in November Middleton topped British Harper's Bazaar's best-dressed list.