Cressida Bonas' big brother has shut down rumors that she'll be getting engaged to Prince Harry.

Jacobi Anstruther-Gough-Calthorpe, 30 spoke with the Evening Standard and said that the press is getting ahead of itself and reporting that his half-sister and the royal are tying the knot anytime soon is "ludicrous."

He revealed that the attention his 24-year-old sister gets from the media is different from his family's "very private" lifestyle.

"It's challenging, you can't deny it. It's not something that is easy for anyone dating a royal or marrying into the family or anyone in the royal family themselves. I think on some level it is different to any other type of fame."

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He continued and said that having a lifestyle of dodging the media isn't easy for Bonas.

"[Cressida] is not a tough cookie at all. She's a very sensitive, sweet girl, all my family are -- they're incredible."

Reports say that the Duchess of Cambridge, Kate Middleton, has taken Bonas under her wing and showed her the dos and don'ts of being a part of the royal family.

An insider said,"Kate has made PR mistakes in the past too. I think she regrets not finding a job to settle down to before getting engaged to William - the 'Waity Katie' tag still haunts her today. So Kate can talk to Cressy about that."

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Bonas and Prince Harry have been dating for about 18 months. While her brother said wedding bells won't be ringing soon for the couple, she's already gotten the "royal seal of approval."

The source said, "Harry is smitten and treats [Bonas] like a princess."

 Prince Harry and Bonas are currently apart while he treks across the South Pole for the Walking With the Wounded expedition. He'll be finishing the competition on Dec. 16 and is expected to be home in time for Christmas.

Tags: Prince Harry Cressida Bonas