Harry and Meghan chose to keep their daughter's birthday in the UK private, celebrating at Frogmore Cottage with close friends and family.
It's unclear which, if any, members of the royal family attended the special occasion, though it's understood the Queen met Lilibet at some point during the Sussexes' stay in the UK.
A spokesperson for the couple said: "Prince Harry and Meghan, The Duke and Duchess of Sussex remain incredibly touched by the countless birthday wishes for their daughter, Lilibet Diana Mountbatten-Windsor, and were amazed to learn that people around the world made donations amounting to over $100K to the World Central Kitchen (WCK) in her honour.
"They extended their gratitude to all who have shown support for the organization, which is especially near to their hearts.
"In honour of Lilibet's 1st birthday, The Duke and Duchess of Sussex invited close friends and family to celebrate. Guests gathered for a casual, intimate backyard picnic at Frogmore Cottage.
"Close family friend and guest, Misan Harriman, who attended Lilibet's special day with his wife and children, took the candid, spontaneous photograph that The Duke and Duchess are pleased to share today."