His mother, Anne Cox married Robin Twist Saturday and Styles was present with his mother throughout the ceremony, reports femalefirst.co.uk. A guest said: "Harry couldn't stop smiling. He hardly left his mum's side and she looked really proud of him. He sipped champagne and talked to everyone."
Styles and Twist were spotted wearing matching black lounge suits, while Cox was in an ivory, floor-length silk dress. The ceremony was held for 42 family and friends and the guests were told about it at the last minute.
An insider revealed: "They chose the medium-priced wedding package. It was a lovely day." Harry was joined by the second best man Mike, Robin's son from a previous relationship and his sister Gemma, 20, was maid of honour.