Shortly after arriving in Berlin with the Duchess of Cornwall, Prince Charles said: "We couldn't be more delighted at the news and we're looking forward to meeting the baby when we return".
"Obviously thrilled, absolutely thrilled, and obviously looking forward to seeing them in the next few days when things have quietened down", William told reporters.
"I'm very pleased and glad to welcome my own brother into the sleep deprivation society that is parenting".
The arrival of Prince Harry and Meghan's baby, who is due to be shown off to the world on Wednesday, is a further boost for heir to the throne Prince Charles.
Around 50 rockets fired at Israel from Gaza: Israeli army
The Israeli military said some 5,200 Palestinians had amassed along the frontier, but did not immediately provide further comment. Reuters also reported that Gaza health officials said four Palestinian bystanders were wounded in one of the Israeli strikes.
Celebrities and world leaders were among those to send messages, a reflection of the star status of Harry, 34, and former USA actress Meghan, 37.
"That's the next bit, but for us I think we will be seeing you guys in probably two days' time as planned as a family to be able to share it with you guys and so everyone can see the baby". But Queen Elizabeth has gradually been managing down her workload in recent years, passing on duties.
Berthelsen said he expects Prince Harry and Meghan's child to have a similar upbringing to his cousins Prince George, Princess Charlotte, and Prince Louis in that he'll likely attend a private school and have privileges thanks to his family's status. Harry said he and Meghan "are still thinking about names".
'These next few weeks are always a bit daunting the first time round so we wish them all the best'. "We're both absolutely thrilled and so grateful to all the love and support from everybody out there", the newly-minted dad said.
James, Alexander and Arthur are among the frontrunners in the latest royal baby name odds, according to bookmakers.
Their message came after an overjoyed Prince Harry, 34, spoke to the press about the birth of his and Meghan's first child.
It's very unlikely that Harry or his son will ever be king because of how many other royals are above them in the line.