24/09/2014 06:44 BST | Updated 20/05/2015 06:12 BST

Duchess Of Cambridge Pregnant: Prince Harry Jokes He Can't Wait To See Brother Prince William Suffer More!

LONDON, ENGLAND - SEPTEMBER 08: Prince Harry poses with Ngati Ranana Maori Dancers as he meets the New Zealand Invictus Team at New Zealand House on September 8, 2014 in London, England. The International sports event for 'wounded warriors', presented by Jaguar Land Rover, is just days away with limited last-minute tickets available at (Photo by Chris Jackson/Getty Images)

Prince Harry has made it clear he will be an emotional rock for dad-to-be (again) Prince William, saying: "I can't wait to see my brother suffer more." You can always rely on a brother's support.

He was joking, of course. We think!

After the Duke and Duchess of Cambridge announced they're expecting their second child, Harry, 29, said the news was 'very exciting' but added, with his tongue firmly in his cheek, that he would 'love to see him try and cope with that' if the couple had a girl this time.

But more seriously, the younger royal referred to Kate's extreme morning sickness.

He said she was 'pretty poorly' but 'doing the best she can'.

Harry added: "I hope the two of them have the opportunity to go through the process again with a little bit of peace and quiet."

Story continues below video.

Prince Harry: 'George Will Be Thrilled'

Yesterday, Prince William admitted it had been a 'tricky few days' after 32-year-old Kate came down with the extreme pregnancy sickness hyperemesis gravidarium, as she did when she was pregnant with Prince George.

The illness forced her to pull out of a planned visit to Oxford University today, prompting Clarence House to announce the baby news.

Kate is being treated by the Queen's surgeon-gynaecologist Alan Farthing and obstetrician Guy Thorpe-Beeston at Kensington Palace.

Her future engagements, including a trip to Malta in three weeks' time – her first overseas solo visit – were being 'reviewed' and may be cancelled.

The gap between Prince George – who, six weeks ago, celebrated his first birthday – and his new sibling will be around 21 months. There are 20 months between Kate and her sister Pippa and the 27 months between William and Harry.

Asked whether he could give the new baby any advice or 'strategy' on being a younger sibling, Harry said: "There's never a strategy. I think George will be over the moon. I think he will be thrilled having another small younger brother or sister."

And when it was put to Harry that the new princess would make him fifth in line to the throne, he laughed and replied: "Great!"

After the announcement, William greeted crowds inside the grounds of St Hugh's College yesterday and spoke to mum Erica Payne, 27, who was with her 12-week-old daughter Isabel - who was being very quiet, William said: "They're good when they stay like that. Quiet."

Apparently, William and Kate had only very recently found out about the pregnancy themselves, but had managed to tell some of their close family last week.

A source said: "Obviously they are delighted, but cautiously delighted because she has not yet reached the 12-week mark.

"It was felt that an announcement needed to be made because people would wonder why she couldn't attend the engagement today."