(CNN) First lady Michelle Obama made quite the fashion statement while having lunch with Queen Elizabeth II at Windsor Palace, but the biggest message might have gone out to the designer of the dress she was wearing.
The first lady, joined by President Barack Obama, wore a two-tone purple Oscar de la Renta dress that cut below the knee while attending a lunch to celebrate the Queen's 90th birthday along with her husband, Prince Phillip.
The designer was an interesting choice, given that on a previous visit to Buckingham Palace in 2009, de la Renta criticized the first lady's fashion choice.
Britain's Queen Elizabeth II, US President Barack Obama, US First Lady Michelle Obama and Prince Philip, Duke of Edinburgh, pose for a photograph in the Oak Room ahead of a private lunch at Windsor Castle in Windsor, southern England, on April, 22, 2016.
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"You don't go to Buckingham Palace in a sweater," de la Renta told WWD in 2009. During that visit, the first lady wore a dark J. Crew sweater, which de la Renta said did not fully show off the American fashion industry.
De la Renta has been vocal on the first lady's fashion choices during her time in the White House. In 2013, he also criticized her for not wearing an American designer to a state dinner for China at the White House.
The Obamas meet British royalty
President Barack Obama, Prince William and first lady Michelle Obama talk with Prince George at Kensington Palace on April 22, 2016, in London.
Obama and the first lady are greeted by Queen Elizabeth II and Prince Phillip after landing by helicopter at Windsor Castle for a private lunch on April 22, 2016.
Philip drives the President, the first lady and Elizabeth from the helicopter into Windsor Castle after the Obama's arrived for a private lunch in Windsor, England, on April 22, 2016.
Elizabeth, the President, the first lady and Philip pose for a photograph in the Oak Room ahead of a private lunch at Windsor Castle on April 22, 2016.
The President, the first lady and the Duke and Duchess of Cambridge meet in London's Buckingham Palace on May 24, 2011.
President Barack Obama meets with Prince Harry in the Oval Office on October 28, 2015.
Queen Elizabeth II poses with the President, the first lady and Prince Philip, Duke of Edinburgh, in the Music Room of Buckingham Palace ahead of a State Banquet on May 24, 2011.
Jill Biden, Prince Harry and Michelle Obama at the Joining Forces Invictus Games 2016 Event at the Wells Fields House on October 28, 2015, in Fort Belvoir, Va.
President Barack Obama sees off Queen Elizabeth II, as the Duke of Edinburgh and the first lady follow after a reciprocal dinner at the Winfield House in London, on May 25, 2011.
Queen Elizabeth II speaks with President Barack Obama during a group photo of world leaders attending the D-Day 70th Anniversary ceremonies at Chateau de Benouville in Benouville, France, on June 6, 2014.
Fashion blogs note that the first lady had not worn an Oscar de la Renta dress while in office until she wore a navy dress by the designer to cocktail party after her White House Fashion Education Workshop in October 2014. De la Renta, a Dominican-born American fashion designer, died less than two weeks later at age 82.
De la Renta was known for dressing every first lady since Jacqueline Kennedy. After his death, former first lady Laura Bush remembered him saying, "We will always remember him as the man who made women look and feel beautiful."