Prince Harry and girlfriend Cressida Bonas are getting serious according to sources after the couple spends the weekend at Sandringham with friends.

It is not the first time that Prince Harry, 29 invited his current squeeze to the Queen's estate in Sandringham but has reportedly invited her to the place on several occasions.

In mid-October, according to the Daily Mail, Cressy was invited by Harry to the Norfolk home of his grandmother. The two reportedly spent a few days at the estate with some friends.

Although the prince is "incredibly serious" about his girlfriend, a close pal says another wedding is "not on the cards - yet."

The party spent three days in Sandringham enjoying the countryside but neither Prince Philip nor the Queen were there, according to sources.

Cressida Bonas has been invited to shooting parties before since Prince Harry's father Charles frequently arranges them when his mother, the Queen, is not in Sandringham.

A source added that Prince Harry and his brother Prince William "are given a weekend each at Sandringham when they can ask some friends to join them." The source however says that there's nothing more to the relationship but that the couple "get on well together."

It is however "too early to say yet what the future holds," the source says.

Fiercely determined to keep Cressida Bonas away from the public eye, Prince Harry is said to be very protective of his current girlfriend. According to the Daily Mail, the prince is acutely aware of how press attention somehow "spooked" his ex-girlfriend Chelsy Davy.

Prince Harry met Cressida Bonas through his cousin Princess Eugenie of York. Princess Eugenie is said to be Cressida Bonas's best friend.

Bonas, described by close pals as "posh, bubbly and terribly, terribly sweet" and her boyfriend Prince Harry are rumoured to wed in 2014.

According to another source, Cressida Bonas is very discreet and that she and Prince Harry "are very fond of each other and taking things one step at a time to ee whether or not there might be something more permanent one day."

Cressida Bonas however is still very young and the source adds that the arrangements do not "include an engagement yet."