Prince William, Duchess Kate Prep for Royal Baby No. 2 in 2015

PHOTO: Catherine, Duchess of Cambridge holds Prince George of Cambridge as Prince William, Duke of Cambridge looks on whilst meeting a Bilby called George at Taronga Zoo on April 20, 2014 in Sydney, Australia. Chris Jackson/Getty Images
Catherine, Duchess of Cambridge holds Prince George of Cambridge as Prince William, Duke of Cambridge looks on whilst meeting a Bilby called George at Taronga Zoo on April 20, 2014 in Sydney, Australia.

While the world waits for another royal bundle of joy to arrive in 2015, Prince William and Duchess Kate, nearing her third trimester, are busy getting prepared for royal baby, part two.

2015 will be a busy year for the royal parents, filled with nursery decorating and pondering baby names in addition to their royal responsibilities and taking care of Prince George.

"She is getting into the home stretch," said Nancy Jeffrey, senior editor of People magazine, whose next issue goes inside Kate Middleton’s baby plans and preparations.

"The biggest priority is making sure her firstborn is lavished with attention he'll soon have to share,” Jeffrey said.

As with any firstborn, Prince George will have to adjust to being a big brother when the new baby arrives in April.

"I think Prince George, in the first instance, might be quite a boisterous big brother,” ABC News royal contributor Victoria Murphy said. “He likes his trucks, he likes to run around Kensington Palace. But I think in the long term we are going to see him be a very caring, very protective big brother to his younger sibling."

With baby No. 2, William and Kate will keep another royal family tradition alive: having two children under 2.

"Prince Charles and his younger sister, Princess Anne, were very close in age. Princes William and Harry are very close in age. You've also got Princess Beatrice and Eugenie,” Murphy said. “I think William wants George to have what he had in Harry, and that's a confidant."

One thing they are expected to do differently this time around is to hire a baby nurse right away.

"Kate will make Anmer Hall her main base with the kids while Will works as an air ambulance pilot,” Jeffrey told ABC News of the 10-bedroom Georgian country mansion. "They will also get their own nanny. ... Last time, for the first few weeks, they tried to go it alone. This time, they are going to bring a baby nurse on board right away."

The duchess is expected to take about nine months off from official duties after the baby arrives, but royal watchers expect to see the proud mom out and about with her little royals in tow soon after.

"Kate is ... very hands on, she's very loving, and ... she wants to raise normal kids," Jeffrey told ABC News. "She is going to face the same kind of challenges juggling two under 2 that many other moms face."