The royal party were marking the 10th anniversary of the Youth Aware Mental Health.

Earlier today, the Duchess of Cambridge displayed her growing baby bump as she and Prince William, were invited for an intimate tea party with some of the youngest members of the Swedish royal family.

William and Kate, who is six months pregnant with the couple's third child, met the adorable offspring of Crown Princess Victoria and Prince Daniel - Princess Estelle, five, and Prince Oscar, who turns two in March.

The Duchess was wearing a cream bouclé dress from Alexander McQueen, while her host wore a mint-coloured trouser suit with a belted waist for their penultimate meeting with the Swedish royals before the couple depart for Norway on Thursday.

This morning, the couple kicked off their second day in Stockholm with a meeting on mental health before stopping in at Matteusskolan school.

While dozens of pupils waved hand-drawn flags and bunches of flowers, some lucky youngsters managed to get a high-five from the Duchess as she greeted the crowds assembled outside. The couple spent around ten minutes shaking hands with the schoolchildren, with William repeatedly telling them 'you've got cold hands' and complimenting them on the flags they were waving.

As the they moved down rows of youngsters, the Duchess asked: 'Are you cold? Are you all wrapped up?'

Some children jumped on each other's shoulders, and hugged each other in excitement at having met the two royal couples. One teenager, more in hope than expectation, quizzed the Duchess about her taste in rap music: 'I asked her if she knew J Hus,' said Lucas Tinseau, 15. 'She said 'I will look out for him.''

William joked to one group about the fact that they had been running late earlier in the day, saying: 'We're not very good with time'

She teamed her outfit with a quilted maroon Chanel bag and fringed leather pumps from Italian label Tod's, while her host, Victoria, opted for a stylish pastel trouser suit worn over a piecrust collar and a Stella McCartney clutch.

The Karolinska Institutet is one of the largest and most prestigious medical universities in the world and accounts for over 40 per cent of the medical academic research conducted in Sweden.

Since 1901 the Nobel Assembly at Karolinska Institutet has also been responsible for selecting the Nobel laureates in Physiology or Medicine.

The Crown Princess has spoken openly about her own battle with an eating disorder as a young woman, while her husband - a former fitness trainer who opened a chain of exclusive gyms, which is how they met - has taken a particular interest in the subject and started his own programme to promote physical well-being in the young.

The two couples left their separate residences but their respective convoys met up en route - and as they stepped out of their cars they greeted each other warmly outside.

Inside they went for a briefing with senior staff including Professor Carl Johan Sundberg, Dr Anna Lundh and Dr Ulrika Berg, who outlined some of their research into the issue.

Maternity style: Duchess displayed her burgeoning bump in a red houndstooth coat by Catherine Walker, worn over an Alexander McQueen dress and paired with earrings by Swedish jeweller In2Design, no doubt in a nod to her hosts.