Positively blooming.

The Duchess of Cambridge attended a reception at Buckingham Palace this evening to mark World Mental Health Day, marking her first public appearance since the news of her third pregnancy was announced. Kate was accompanied by her husband William, the Duke of Cambridge, and his brother Prince Harry but all eyes were on the expectant mother. The trio made a point of thanking people who have campaigned for mental health awareness in recent times as the event acknowledged their tireless work in such an important field.

Bump just visible as Kate makes her first appearance since her third pregnancy is announced pic.twitter.com/5NuTp9swdr

— Victoria Murphy (@QueenVicMirror) October 10, 2017

On #WorldMentalHealthDay, The Duke & Duchess and Prince Harry attend a reception to celebrate those working in the mental health sector. pic.twitter.com/jmWcnWafm6

— Kensington Palace (@KensingtonRoyal) October 10, 2017

Pregnant Kate makes her first appearance in a dress by Temperley pic.twitter.com/73gsvEHPmm

— Victoria Murphy (@QueenVicMirror) October 10, 2017

The 35-year-old wore a mid-length green lace Temperley dress for the occasion and looked as elegant as always.

The #DuchessofCambridge is wearing Temperley tonight. Screen grab of her from @QueenVicMirror Twitter video! pic.twitter.com/AfAHZJ6z0L

— HRH Kate Middleton (@princesskate_GB) October 10, 2017

Duchess of Cambridge as she makes her first public appearance since her third pregnancy confirmed last month. She's still suffering from HG pic.twitter.com/H4VVVuk6J3

— Rebecca English (@RE_DailyMail) October 10, 2017

Kate' last public engagement was on August 30th when she accompanied her husband and brother-in-law to the Princess Diana memorial garden. According to reports, the royal couple will welcome baby number three, a sibling to Prince George (4) and Princess Charlotte (2) early next year but a due date has yet to be confirmed. It has been suggested that the Duchess has again been suffering from Hyperemesis Gravidarum with her third pregnancy which forced her to miss a number of recent public engagements, including her son Prince George's first day at school.