The Duchess of Cambridge has been given a gift every pregnant woman travelling on the London Underground probably needs - a "Baby on board" badge.
Kate still has a slim figure but, at five months pregnant, her baby bump is growing by the week.
She was given the practical present as she joined the Queen and Duke of Edinburgh at Baker Street Tube station to celebrate the 150th anniversary of the transport network.
The engagement was the Queen's first public event in more than a week but she looked well and chatted to senior London Underground managers, train drivers and station staff during her visit.
The Queen, who has been suffering the symptoms of gastroenteritis, had been forced to miss a number of engagements since she was first declared ill by Buckingham Palace almost three weeks ago.
As the royal party stood on a platform, London Underground chief operating officer Howard Collins made the presentation of the white badge printed with the words "Baby on board" and featuring the famous London Underground roundel.
Watching guests laughed as Mr Collins handed over the gift and Kate held it against her teal-coloured Malene Birger coat and joked "I'll make sure I wear it at home".
Mr Collins said afterwards: "Kate said 'Oh yes, I've seen this before'. She used to travel on the Tube so she probably saw them then.
"She asked me 'How do they work?' and I said they're fantastic, they really do make a difference - saves men the embarrassment of having to guess if a woman is pregnant.
"She asked so many great questions of the staff and seemed really interested in our work."
The badges, available from Transport for London (TfL), overcome the awkwardness often felt by pregnant women of having to ask someone to give up their seat.