The Duchess of Cambridge has retreated to the comfort of her parents home while she continues to struggle with acute morning sickness, according to reports.

Kate, who is around ten weeks pregnant with her second child, returned to her family's £5million Georgian mansion in Bucklebury, Berkshire this week with her 15-month-old son, Prince George.

Sources claim that the Duchess "hasn't been well at all" as she once again battles hyperemesis gravidarum - a condition which causes severe vomiting in pregnant women.

Her mother Carole Middleton is apparently taking charge of her daughter's recovery by researching alternative sickness cures on the internet - such as herbal tea.

Mrs Middleton has also been taking care of her grandson, sparking gushing responses on Twitter from excited fans of the adorable Prince.

After being seen in a local shop with the royal tot, a shop assistant tweeted: "Served Kate Middleton's mum and Prince George today at work. He is gorgeous!"

The Duchess has previously said she feels much more relaxed at her parent's home than at Kensington Palace, where she resides with Prince William.

One source was quoted as saying: "Kate is feeling so lousy that she just wanted to be with her family and out of public view.

"She is extremely close to Carole, who is very much a hands-on grandmother."

The Duchess has not been seen in public since Buckingham Palace was forced to announce her pregnancy last month, several weeks earlier than intended.

Her illness also forced Kate to cancel all her upcoming royal engagements, at least for the next two weeks.

Buckingham Palace announced yesterday that Kate is expected to take part in a state visit of the president of Singapore on October 21.

However, a source warned that her attendance will be reviewed nearer to the time.

The Duchess suffered from the same condition during her first pregnancy with Prince George and was hospitalised with severe dehydration.

Hyperemesis gravidarum is thought to affect around 15 per cent of all pregnancies and is said to increase the chance of the woman giving birth to twins.

This had led to speculation that there could be two new royal siblings for Prince George.

Rumours are rife that the royal couple are expecting twin girls - although official sources from the palace have yet to confirm this.