Prince Harry
Prince Harry is turning 30 on 15 SeptemberReuters

Prince Harry is turning 30 on 15 September and to mark the important occasion, Kate Middleton and Prince William are organising a private party at Kensington Palace, where they will be hosting a dinner for 30 of Harry's friends.

Harry's former girlfriend, Cressida Bonas, 25, was supposed to be in charge of planning the party, however, the couple split up in April 2014.

Nightclub theme

There are rumours that one room of the palace will be given a nightclub theme, featuring Harry's favourite songs.

The nightclub idea was meant to be a surprise, although Harry said he knew about the plan.

St. Moritz theme

According to the Express, another room will be will be decorated to resemble the royal family's Swiss ski resort, with white leather sofas and drapes.

Harry 'cannot misbehave'

According to Royal Watch writer Katie Nicholl, Harry's best friend, nightclub owner Guy Pelly, offered to throw a party for the prince on his actual birthday, at Sloane Square hot spot Tonteria.

"Harry would like to go, but he knows he can't have a crazy night out and misbehave," a source told Nicholl. "For him, September is all about the Invictus Games and he doesn't want anything overshadowing that."

Another source told the Sun newspaper, "This is an important birthday for Harry and he's not going to fall out of a club late at night. He's keen to show he's come of age."

Old flames return

According to a report by the Mirror, at least two of Harry's old flames, Cressida Bonas and Chelsy Davy, 28, are expected to be present at the party.

An insider said: "Harry has no problem with seeing his exes all under the same roof. Let's just hope they don't either."

Will Egyptian Muslim Heiress attend?

There are rumours doing the rounds that Harry is dating Enayat Younes, an Egyptian heiress.

Harry met Younes at the Hairy Lemon nightclub in Sotogrande. They were later spotted together at a posh resort.

It was reported that Younes, the daughter of Egyptian entrepreneur Farouk Younes, can trace her lineage to the country's royal family.

Will she be at the party?

Birthday supper

In addition to overseeing all the arrangements for the celebration, Kate is due to be cooking a birthday supper for Harry.