The Duchess of Cambridge is due to give birth in July and could resume her royal duties as early as next month after recovering from her pregnancy sickness, aides said on Monday.
The Duchess, 31, had a 12-week scan earlier this month showing that her unborn baby is in good health, prompting St James's Palace to announce the expected birth month.
It means that the Duchess was only about six weeks pregnant when she and the Duke were forced to disclose that she was pregnant during her hospital stay at the start of December. She is now thought to be 13 to 14 weeks into her pregnancy.
The Duchess was suffering from a severe form of pregnancy sickness called hyperemesis gravidarum, but has made such a good recovery that she is expected to resume a near-normal official workload from next month.
One insider said, "Although the nature of the Duchess's condition is that it can come back, she is much better and, health permitting, she will be back doing public engagements in the next couple of months."
Although the Duchess made a brief appearance at the BBC's Sports Personality of the Year awards before Christmas, she has not carried out a full day of engagements since her pregnancy was announced, and has stayed in the South East, close to her family, rather than spending time with the Duke at their remote farmhouse on Anglesey.
Bookmakers installed July 17, the Duchess of Cornwall's birthday, as the favourite date for the baby to be born. But those who bet on twins have already lost their stake after the Palace confirmed that the Duchess was carrying only one baby.
A July birth is likely to provide a welcome boost to the economy, because it means that Britain's favourite "brand" with foreigners, the Royal family, will feature prominently in news coverage as the tourist season gets into full swing.
Mark Di-Toro, of Visit Britain, said, "The challenge for 2013 is to maintain the momentum created last year by the Olympics and the Diamond Jubilee, and this will certainly help. The monarchy and Royal palaces are very much a part of the cultural heritage side of the tourism industry, which brings in 4.5 billion pounds every year and is the biggest sector within our tourist industry.
"So to have a royal baby arriving in the summer will be an opportunity to encourage people to visit places associated with the Duke and Duchess."
Royal aides said the Duchess was expected to return to Anglesey in the next few weeks, but she is not expected to travel abroad either before or immediately after the birth.