Louis, 12 weeks old today, slept through the entire ceremony but was pictured alert and with a wide opened-mouth smile as he was held upright by his mother in the gardens of Clarence House.
The new picture was released on social media at 10am today, nearly 12 hours after Kensington Palace put out another four shots from the day last night.
The palace tweeted this morning: ‘The Duke and Duchess hope that everyone enjoys this lovely photograph of Prince Louis as much as they do.’
Louis was wearing a replica of the royal christening robe, made of fine Honiton lace lined with white satin, which was created in 1841 for Queen Victoria’s eldest daughter, Victoria, Princess Royal.
That gown was worn for all subsequent royal baptisms including the present Queen, her children and grandchildren.
Kate wore a cream Alexander McQueen dress with a floral headpiece by Jane Taylor, and her long hair was swept back in a bun.