Prince Harry and his girlfriend Cressida Bonas are getting more serious and the media can't wait for a royal engagement - but will Cressida Bonas have to go through "princess boot camp" first? Prince Harry's girlfriend Cressida Bonas was caught doing something in public that Kate Middleton, Prince William's wife, would "never" get caught doing. What was it?

According to TheSpec.com, Cressida Bonas was caught braiding her hair in public while she joined Prince Harry for her first official engagement by his side, when he gave a speech at We Day at the Wembley Arena in London.

"The Palace was appalled to see her plaiting her hair in public when she went to support Harry at Wembley," a source told the Daily Star newspaper.

"Kate [Middleton] would never be caught doing something so out there."

Cressida Bonas will likely never escape comparisons between herself and Kate Middleton - and she better get used to it because rumors are suggesting that Prince Harry's girlfriend and Prince William's wife are soon to be sister-in-laws.

According to TheSpec.com, many believe Prince Harry will propose to girlfriend Cressy before his 30th birthday in September. Fans of the couple are counting on the royal and his girlfriend getting engaged before the end of 2014.

According to a royal source, the 29-year-old royal and his 25-year-old girlfriend have already started planning their future, E! News reports.

"Cressida has also had initial talks with the palace about what will happen once they do announce their engagement and the way things will work. Harry has told his crowd that he knows he will wed Cressida but he wants to ensure their life doesn't become a circus. He's not half as important as William with regards to the throne and wants his privacy to reflect that. They want to be able to enjoy normality far more than Wills and Kate can. They're not surrounded by the protocol like the elder royals-they can sway the opinion as young royals. They both feel they deserve the chance to live out their married life in as normal a way as possible."

The royal insider added that Kate Middleton has been giving Cressy advice on how to deal with being engaged to a royal.

"Kate's been brilliant with Cressida and has been giving her advice," they say. "She likes her very much and has offered her tips on how to keep her normality. Kate's been there and done it and, while she knows Cressida won't be as talked about and followed like she was, she needs to get a real slant on what happens."

Harry and Cressy have been dating since early 2012.