Prince Harry has said he "can't wait to be an uncle".
The 28-year-old army captain was in Afghanistan when the news broke that the Duke and Duchess of Cambridge were expecting their first child, but he revealed he called home to congratulate his brother and sister-in-law.
Prince Harry hopes his sister-in-law will be able to enjoy her pregnancy in peace
Harry will be replaced as the third-in-line to the throne when the royal baby is born in July this year.
"Obviously I'm thrilled for both of them," he said in Helmand Province about ten days after St James's Palace announced that Kate was pregnant.
"It's about time," he joked. "I can't wait to be an uncle."
Asked if he had telephoned William and Kate to congratulate them from Afghanistan, he said: "Of course I have. I had a chat to them."
The Apache pilot revealed the couple were "both very happy" and rubbished press reports he had written a letter or sent Kate a text message.
"I didn't send a letter of congratulation like most of the papers said.
"How any of the papers think that they know the relationship between myself and my sister-in-law is quite remarkable.
"But they're wrong, as always.
"I spoke to my brother and her, and they're both very well and both very happy obviously."
After Kate was admitted to hospital with acute morning sickness, the world's press gathered in London, but Harry said he hopes the future Queen can be left in peace in the coming months.
He said: "I think it's very unfair that they were forced to publicise it when they were, but that's just the media for you.
"And I literally am very very happy for them, but I just only hope that she and him - but mainly Catherine - hopefully that she gets the necessary protection to allow her as a mother-to-be to enjoy the privacy that that comes with.
"I seriously hope that's going to be able to happen."
Harry is currently "100% single", according to reports, and his wild antics in Las Vegas before his tour of duty show he is still living up to his "Playboy Prince" reputation.
Asked if there was pressure on him to settle down like his older brother, he said: "I don't think you can ever be urged to settle down.
"If you find the right person and everything feels right, then it takes time, especially for myself and my brother."
The royal said it will be a slow process.
"You ain't ever going to find someone who's going to jump into the position that it would hold," he said.
"Simple as that."