Kate Middleton
Kate Middleton has been suffering from a severe form of morning sickness - hyperemesis gravidarum.Getty

Kate Middleton continues to suffer from severe morning sickness and Prince William is on talks with her medical team all the time.

The Duchess of Cambridge, who is pregnant with her second child, has been suffering from a severe form of morning sickness - hyperemesis gravidarum.

It was previously reported that Kate has returned to her family home in Bucklebury, Berkshire, with Prince George.

"Kate often starts the morning feeling great, but then she'll take a turn by afternoon. It's not fun for her at all," a royal source told the Boston Herald.

"Her nausea is definitely worse this time. It's been a hellish few weeks."

Kate "has taken everyone by surprise. Fortunately, the baby is well, and she's ­doing her best to stay healthy," the insider said.

Prince William is by her side as she suffers from pregnancy sickness.

"It's been so difficult, but she has all the people she loves around her," the source said.

"William's been amazing throughout all of this. He's in constant communication with the doctors. He doesn't like seeing Kate unwell and just wants her to get better so they can enjoy the rest of the pregnancy," the insider added.

Meanwhile, on 21 October, Kate and Prince William will welcome Singaporean President Tony Tan to Britain, Buckingham Palace has confirmed.