The party supply company is now selling its cups, hats, balloons and table runners at Saker ShopRite grocery stores, the Asbury Park Press reported.
Middleton, the mother of Catherine, Princess of Wales, toured the aisles at several stores, including one in Middletown, New Jersey, where the products are for sale.
The company is now featured in 39 Saker ShopRite stores, with plans of a larger U.S. expansion in the future. Last year, Party Pieces started selling its products online in the U.K., People magazine reported.
Middleton said in the past that she was inspired by her children — Kate, Pippa and James — to start the business.
“My children inspired my business and have been involved from the start,” Middleton told The Daily Mail last year. “The success that we’ve had has helped us build the life we have currently. I feel incredibly fortunate to have found the professional fulfillment I always wanted.”
Middleton had said that when she was shopping for items for the now Princess’ fifth birthday, she was disappointed by what she found.
“All I could find were basic clown plates,” Middleton said, according to People magazine. “I realized there was a gap in the market for party ware that wasn’t too expensive and which looked good, so [I] decided to design my own. I took some prototypes to various High Street retailers and was turned away.”
Middleton then started the business in her kitchen and marketed it to the parents at her children’s nursery school.
This is the first partnership in the U.S. since Middleton founded Party Pieces in 1987, the Asbury Park Press reported.
Photos: Kate Middleton through the years Kate Middleton as a 5-year-old. (Middleton Family/Clarence House/Getty Images )
Photos: Kate Middleton through the years Kate Middleton, back row, third from left, is pictured in a tennis team photo during her time as a pupil at St Andrew's School in Pangbourne, England, where she attended from 1986 to 1995. (St Andrew's School - WPA Pool/Getty Images)
Photos: Kate Middleton through the years Kate Middleton and her father, Michael Middleton, before her graduation from the University of St. Andrews in June 2005. (Indigo/Getty Images)
Photos: Kate Middleton through the years Kate Middleton does some shopping during the Gatcombe Park Festival of British Eventing in August 2005. (Anwar Hussein/Getty Images)
Photos: Kate Middleton through the years Prince Harry, left, Prince William, center, and Kate Middleton cheer on the English team during the RBS Six Nations Championship match between England and Italy in 2007. (Richard Heathcote/Getty Images)
Photos: Kate Middleton through the years Kate Middleton takes part in a training session with The Sisterhood cross channel rowing team on the Thames in August 2007. (Max Mumby/Indigo/Getty Images)
Photos: Kate Middleton through the years Kate Middleton and Prince William announced their engagement in November 2010. ( Chris Jackson/Getty Images)
Photos: Kate Middleton through the years The Duke and Duchess of Cambridge attend the Calgary Stampede in 2011. (Samir Hussein/WireImage)
Photos: Kate Middleton through the years Kate Middleton, right, sits with her sister, Pippa Middleton in the Royal Box during the 2012 Wimbledon men's final between Roger Federer and Andy Murray. (Clive Brunskill/Getty Images)
Photos: Kate Middleton through the years Kate Middleton plays hockey with the GB hockey teams at the Riverside Arena in 2012. (Chris Jackson - WPA Pool /Getty Images)
Photos: Kate Middleton through the years Kate Middleton and Queen Elizabeth II enjoy a children's sporting event in 2012. (Phil Noble - WPA Pool/Getty Images)
Photos: Kate Middleton through the years Prince William, Duke of Cambridge and Kate Middleton, Duchess of Cambridge, depart The Lindo Wing with their newborn son, Prince George, at St Mary's Hospital on July 23, 2013, in London. (Photo by Chris Jackson/Getty Images) (Chris Jackson/Getty Images)
Photos: Kate Middleton through the years Kate Middleton waves her wand and casts a spell on the set used to depict Diagon Alley in the Harry Potter Films during the Inauguration Of Warner Bros. Studios in Leavesden in 2013. (Paul Rogers - WPA Pool/Getty Images)
Photos: Kate Middleton through the years Kate Middleton tries her hand at cricket during the countdown to the ICC Cricket World Cup on April 14, 2014, in Christchurch, New Zealand. (Joseph Johnson/Getty Images for ICC Cricket World Cup)
Photos: Kate Middleton through the years The Duke and Duchess of Cambridge and Prince Harry spearheaded a campaign called Heads Together in 2016. (Nicky J Sims/Getty Images for Royal Foundation)
Photos: Kate Middleton through the years The Duke and Duchess of Cambridge pose with Prince Louis after his birth in 2018. (Samir Hussein/WireImage)
Photos: Kate Middleton through the years Kate Middleton and Meghan Markle attend Wimbledon in 2018. (Karwai Tang/WireImage)
Photos: Kate Middleton through the years. Princess Charlotte arrives for her first day of school, with her brother Prince George and her parents the Duke and Duchess of Cambridge, at Thomas's Battersea in London on Sept. 5, 2019, in London. (Aaron Chown - WPA Pool/Getty Images)
Photos: Kate Middleton through the years The Duke and Duchess of Cambridge visit Badshahi Mosque during their royal tour of Pakistan in October 2019. (Owen Humphreys - Pool/Getty Images)
Photos: Kate Middleton through the years The Duke and Duchess of Cambridge enjoy some sports during a 2020 trip to Ireland. ( Charles McQuillan/Getty Images)
Photos: Kate Middleton through the years Kate Middleton, the Duchess of Cambridge, center, is flanked by Camilla, Duchess of Cornwall, and Sophie, Countess of Wessex, on the balcony overlooking the Cenotaph during the National Service of Remembrance on Nov. 14, 2021, in London. (Richard Pohle - WPA Pool/Getty Images)
Photos: Kate Middleton through the years Kate Middleton, left, chats with U.S. Open champion Emma Raducanu as they return to the LTA's National Tennis Centre for The Homecoming on Sept. 24, 2021 in London. (Chris Jackson/Getty Images for LTA)
Photos: Kate Middleton through the years The Duke and Duchess of Cambridge take part in a land yachting session on West Sands beach in May 2021. (Max Mumby, pool/Getty Images)
Photos: Kate Middleton through the years Kate Middleton tries her hand at archery during a 2021 visit to Wolverhampton, England. (Jacob King - WPA Pool/Getty Images)
Kate Middleton Through the Years SANDRINGHAM, ENGLAND - SEPTEMBER 15: William, Prince of Wales and Catherine, Princess of Wales, look at floral tributes, following the death of Britain's Queen Elizabeth, at Sandringham Estate on September 15, 2022 in Sandringham, England. (Photo Toby Melville - WPA Pool/Getty Images) (WPA Pool/Getty Images)
Kate Middleton Through the Years LONDON, ENGLAND - SEPTEMBER 19: Kate Middleton, Princess of Wales is driven down The Mall after the funeral for HM Queen Elizabeth II's funeral on September 19, 2022 in London, England. Elizabeth Alexandra Mary Windsor was born in Bruton Street, Mayfair, London on 21 April 1926. She married Prince Philip in 1947 and ascended the throne of the United Kingdom and Commonwealth on 6 February 1952 after the death of her Father, King George VI. Queen Elizabeth II died at Balmoral Castle in Scotland on September 8, 2022, and is succeeded by her eldest son, King Charles III. (Photo by Tom Jenkins - WPA Pool/Getty Images) (WPA Pool/Getty Images)
Kate Middleton Through the Years CARRICKFERGUS, NORTHERN IRELAND - OCTOBER 06: Catherine, Princess of Wales pictured during her visit to Carrickfergus on October 6, 2022 in Carrickfergus, Northern Ireland. Prince William, Prince of Wales and Catherine, Princess of Wales are on a one day visit to the province. (Photo by Charles McQuillan/Getty Images) (Charles McQuillan/Getty Images)
Kate Middleton Through the Years LONDON, ENGLAND - OCTOBER 13: Catherine, Princess of Wales plays boccia as she attends the 10th Anniversary Celebration of Coach Core at Copper Box Arena on October 13, 2022 in London, England. (Photo by Heathcliff O'Malley - WPA Pool/Getty Images) (WPA Pool/Getty Images)
Photos: Kate Middleton through the years Catherine, Princess of Wales attends the Christmas Morning Service at Sandringham Church on December 25, 2023 in Sandringham, Norfolk. (Photo by Stephen Pond/Getty Images) (Stephen Pond/Getty Images)