In celebration of Queen Elizabeth's 90th birthday on April 21, those close to her sat down with ITV to look back fondly on their memories together. Kate Middleton, who joined the royal family in 2011, shared an anecdote about her first Christmas with the Queen and her struggle to find the perfect gift.

In an interview to be included in "Our Queen at Ninety," the Duchess of Cambridge said she was completely stumped as to what to get Queen Elizabeth II that Christmas. After racking her brain she decided to keep it simple — opting to gift her with something her own grandparents would enjoy. Middleton, 34, said that she felt a homemade gift was her best bet, though she knew it "could have gone horrible wrong." The Duchess got in the kitchen and whipped up her granny's chutney. Much to Middleton's surprise Queen Elizabeth II was a big fan of the recipe, which later was featured in Pippa Middleton's 2012 cookbook.

"I was slightly worried about it, but I noticed the next day that it was on the table," the Duchess said. "I think such a simple gesture went such a long way for me and I've noticed since she's done that on lots of occasions and I think it just shows her thoughtfulness, really, and her care in looking after everybody."

In addition to the airing of "Our Queen at Ninety," Queen Elizabeth II will be treated to a special luncheon in celebration of her 90th birthday. On June 12, nearly two months after her actual birth date, a Patron's Lunch will be held. The event is being organized by the Queen's grandson, Peter Phillips, and will feature 10,000 guests. Attendees will be treated to a picnic-style lunch inside custom baskets — or hampers — created by Marks and Spencer. The brand tweeted a photo of the custom basket, which features bright blue accents, on March 21. According to their most recent message the basket will be filled with "the very best of British produce and ingredients. 

"Our Queen at Ninety" was announced on Feb. 1 by Entertainment Tonight. The publication reported that the two hour special would feature interviews from members of the royal family, including Middleton. "Our Queen at Ninety" serves as the first television interview the Duchess has done since 2010 when she and Prince William got engaged. 

The TV documentary airs Sunday, March 27 at  8 p.m. GMT in the United Kingdom on ITV.