Kate and William's first stop in their trip to Ireland was to a soccer stadium where the couple learned about programs that encourage young girls to play the sport and those dealing with mental health issues.
The Cambridge's are in for a busy week at the beginning of March.
He added: "Mary Peters is not only one of the United Kingdom's sporting legends, she's also inspired generation after generation to come together in times of trouble and work for the common good - a lesson I hope many of us can learn from".
The royal event will be the first time Meghan Markle and Kate Middleton are seen together since Christmas a year ago.
The Duke and Duchess of Cambridge kicked off a surprise royal tour of Northern Ireland on Wednesday.
William also told a young boy that his five-year-old son George loves animated action film How To Train Your Dragon.
William then took to the stage to make a brief speech.
"Will spoke to young people who take part in drama work shops and they did arts and crafts together".
While shaking hands and waving goodbye to her fans the Duchess said: "I think William may be slightly worried" in response.
"A lot of people have speculated that she'll have three children as per her own family". It's very nice to meet you.
Ian Paisley, MP for North Antrim, gifted William with a Blackthorn walking stick.
"The Blackthorn stick is harvested and made in Northern Ireland". One mother, Rebecca White, said Kate praised new moms who have struggled with breastfeeding.
The visit to Ballymena comes after a range of high-energy engagements on Wednesday. Later in the day, they poured some pints at Belfast's Empire Music Hall.