The Duchess chats with Nicola Adams MBE - the first woman to win an Olympic boxing title.
An arrival video from Kensington Palace.
The Duke & Duchess of Cambridge and Prince Harry are meeting #Rio2016 @TeamGB & @ParalympicsGB at the #GBHeroesLDN reception. pic.twitter.com/VRUjHHyebC— Kensington Palace (@KensingtonRoyal) October 18, 2016
Other royals in attendance included the Princess Royal, who is president of the British Olympic Association, the Duke of York, the Duke of Kent and the Duke and Duchess of Gloucester. Princess Eugenie was scheduled to attend but was unable to make it.
Below, Princess Anne introduces Lord Coe to the Queen. Her Majesty looked regal as ever in an Angela Kelly kingfisher and petrol blue dress.
Prime Minister Theresa May curtsies to the Queen.
Ahead of the reception, Kensington Palace tweeted: "The Duke and Duchess of Cambridge and Prince Harry are very much looking forward to attending tonight's reception." They added that Kate's patronage SportsAid has supported many successful athletes including Tom Daley and Ellie Simmonds.
Prince William admires Ellie Simmonds' gold medal. Ellie is a British Paralympian swimmer competing in S6 events. She came to national attention when she competed in the 2008 Summer Paralympics in Beijing, winning two gold medals for Great Britain, despite being the youngest member of the team, at the age of 13. In 2012 she was again selected for the Great Britain squad, this time swimming at a home games in London. She won another two golds there, and set a world record in the 400m freestyle. She won another gold medal at the Rio Paralympics in 2016, this time setting a world record for the 200m medley.
Ellie looked delighted to meet the royals, especially Her Majesty.
It's been a very special day for Team GB. The athletes participated in a gilded victory parade today to celebrate their incredible performance at Rio 2016.
Team GB and Paralympic GB brought home a combined 214 medals, coming second in both medal tables. The fantastic results mean Britain is the first ever country to improve on their performance at the games following immediately after one they hosted.
The athletes looking very sharp in their formal wear by Simon Jersey before the reception began.
William and Kate met with Team GB's women's hockey team.
Kate, who has been a keen hockey player since her school days, enjoyed chatting to the ladies about their experiences at Rio.
Discussion with the athletes quickly turned to George and Charlotte. Emily Andrews reported: "Kate said Charlotte is loving learning to ride, while George was using his polo stick as a hockey stick - much to her delight. And although Kate doesn't share Charlotte's passion for horses, she's said she'll champion and encourage it as much as possible."
'Kate spoke as she joined husband William and the Queen honouring Olympians and Paralympians at a Buckingham Palace reception. Equestrian triple-gold medalist Natasha Baker had a good chat with Kate. The Duchess told her: "George is fascinated by fencing but I think that's because of the face shields. "Charlotte would have loved to be here but she'd be running riot!"
Afterwards the Paralympian said: "I asked her how the children were and she said Charlotte is really enjoying her riding which is great to hear and I said we may see her here on a line-up in 20 years time. "She emphasised that Charlotte has this passion about horses and although she doesn't echo it, she'll do her best to champion and encourage it."
The Duchess debuted a new bespoke poppy print Alexander McQueen dress this evening.
Kate's dress appears to be a customised version of the pre-spring 2017 style shown below (with thanks to @katiemidleton). The Silk Floral Midi Dress retails for $3075 at Saks Fifth Avenue. There are several differences between the original style and Kate's dress, most notably the addition of long sleeves and a closed back.
More from the Telegraph's Bethan Holt:
"The collection was inspired by the intricately beautiful hand painted patterns seen in British folk art, with designer Sarah Burton recreating colourful flowers on dramatically flounced mini dresses and maximalist tiered skirts.
Of course, translating such a richly detailled offering for the needs of a future queen has become a speciality of the Alexander McQueen team; the silk dress worn by the Duchess tonight came with an elegant v-neck, nipped-waist and long, cuffed sleeves.
It's likely that the dress chosen tonight was part of the same order as that worn in Canada as both come from the same collection."
The poppies feature considerably in McQueen's Resort 2017 Collection. In their review of the collection Vogue reported: "The mixtures of carnations, yellow roses, peonies, and poppies, each petal expertly defined with an artist’s paintbrush, were inspired, she said, by British folk art and domestic interiors: 'Wallpaper, patterns you see on canal barges.'"
A look at the print on McQueen's Poppy Print, Drop-Waist Dress.
Kate teamed the dress with her red suede Gianvito Rossi pumps.
The Duchess carried her red Miu Miu Bow Embellished Suede clutch. The £640 bag is described: "Crafted in Italy from plush crimson suede. This ladylike style has a gilded silver chain strap and opens to three spacious compartments - including a secure zipped section. Use the internal mirror to refresh your lip color on the go." It's currently available at Net-A-Porter.
Kate completed the look with her £130 Soru Jewellery Baroque Pearl Double Sided Earrings. The earrings are described: "18ct Yellow gold vermeil on sterling silver earrings. Hand crafted with iridescent baroque pearls edged with multi faceted Swarovski crystals. Length of stones: 2-3cm approx, stone sizes vary slightly as no two pearls are the same making your earrings totally unique to you."
A brief wrap up of the event from Kensington Palace.
The Duke and Duchess of Cambridge and Prince Harry welcome the @TeamGB and @ParalympicsGB medallists to Buckingham Palace! #GBHeroesLDN pic.twitter.com/XFKUlojyRT— Kensington Palace (@KensingtonRoyal) October 18, 2016
In other news, Kate has written the foreword for the GCHQ's (the UK's national intelligence and security agency) new puzzle book. The Duchess' decision to write the foreword was based on two reasons: her grandmother, Valerie Glassborrow, worked at Bletchley Park during the Second World War, and sales of the book will support William and Kate's mental health campaign, Heads Together.
In the foreword Kate speaks of how proud she has always been of her grandmother: "I have always been immensely proud of my grandmother, Valerie Glassborrow, who worked at Bletchley Park during the Second World War. She and her twin sister, Mary, served with thousands of other young women as part of the great Allied effort to break enemy codes. They hardly ever talked about their wartime service, but we know now just how important the men and women of Bletchley were, as they tackled some of the hardest problems facing the country."
The Duchess continued: "In a new century, their successors at GCHQ continue this intellectual tradition. Like their Bletchley predecessors, they have become well known for valuing neurodiversity and understanding the importance of mental well-being. William, Harry and I are very grateful that this book is supporting our Heads Together campaign. I hope it will not only amuse and challenge readers, but help to promote an open discussion of mental health problems, which can affect anyone, regardless of age or background."
The book will feature more than 140 pages of codes, puzzles and challenges created by GCHQ's expert code-breakers in their spare time. These will range 'from easy to mind-bending' and include ciphers and substitution codes, tests of numeracy and literacy, and picture and music challenges. It will be available on Thursday, 20 October.
We'll be back with the remaining tour polls next!