Now marking its tenth year, the awards celebrate the selfless, brave and exceptional achievements of young people. It is the biggest annual teen event in the pop music calendar.
Celebrities and stars in the music, sporting and online industries are also honoured.
William and Kate met with the finalists and joined well-known faces including performer Camila Cabello and BBC Radio 1 DJs Clara Amfo and Greg James.
Ms Cabello said: “I was so honoured to be invited to Kensington Palace to meet and celebrate this year’s Teen Hero finalists with The Duke and Duchess of Cambridge. Hearing the incredible things these Teen Heroes have done is so inspirational! Their passion and dedication to help others is amazing and they really blew me away!”
More on the background of three of the finalists from BBC Radio 1:
'12 year-old Hazel lives with a rare genetic disorder called Xeroderma Pigmentosum (XP) which limits the body’s ability to repair damage caused by UV light. After being diagnosed at age 3 Hazel was advised by doctors to stay indoors indefinitely, but she has since learnt how to manage the condition safely in her daily life with support from charities and specialist clinics. Hazel has raised awareness of XP by making a film and giving talks to schools in her local area, and has raised £2000 for the charity that supported her by climbing the 900m high Ben Lomond mountain earlier this year in her protective clothing.
Rachel, aged 17, campaigns for change and better futures for young people in the UK. She is a volunteer for her local youth council and a member of the UK Youth Parliament, and has won a Diana Award for her work towards tackling cyber bullying. Rachel is also chair of the UK Youth Select Committee, which this year has been focussed on knife crime.
14 year-old Scarlett is a young carer to her mother, older sister and grandmother. Both Scarlett and her mum have an incurable nerve condition called HNPP, which can make everyday activities like carrying shopping bags extremely painful. As well as helping her mum, Scarlett cares for her sister, who has type 1 diabetes, and her grandmother, who has depression. A typical day for Scarlett, who also has autism, includes house chores, gardening, walking her grandmother to church and entertaining the other church goers.
It is the fourth consecutive year William and Kate hosted finalists at Kensington Palace. In 2016, they welcomed young people and representatives from the awards. Kate, who wore a bespoke McQueen dress told, Joe and Toby, who were both active fundraisers for Cancer Research UK. "I don't know how all of you find the time to do the volunteering," she told them. "It's such a great thing... Keep it up." William added, "Massive congratulations, it's seriously impressive," before them the group of winners as "shining lights".
Last year, they met teenager Siena who shared her experience of meeting the couple with Hello!: "The Duchess was especially interested in addressing autism stereotypes and was saddened to hear about the severity of the disability-related bullying I have experienced. She congratulated me for being a Diana Award holder and for currently serving on the National Youth Board, a role that has given me a national platform through which to share my disability-based bullying experience. They were both incredibly warm, supportive and encouraging. Meeting them was an awesome experience! They have inspired me continue to make a positive difference in my community."
The Duchess selected L.K. Bennett's Gabrielle Abstract Midi dress in toffee and black for the occasion (with thanks to Kate Middleton Style).
The £395 piece is described as: "Inspired by 30s style with exaggerated shoulders and ruching through the front, the Gabrielle midi dress from L.K.Bennett offers a soft, smooth feel thanks to the stretch silk fabric, printed with a vintage archive pattern that gives it a statement aesthetic." It's available in several sizes at John Lewis.
The winners will be presented with their awards on Sunday, 24 November.