|Styles was the best man at his mother's wedding
Anne Cox married Robin Twist this weekend and the One Direction heart throb barely "left" his mother's side at the ceremony in Cheshire, England.
A guest told the Sunday Mirror newspaper: "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."
The 19-year-old pop superstar and Robin wore matching black lounge suits, while Anne was seen in an ivory, floor-length silk dress.
The ceremony - held for 42 family and friends - was kept a secret with guests only told at the last minute.
An insider revealed: "They chose the medium-priced wedding package. It was a lovely day."
Harry was joined by second best man Mike - Robin's son from a previous relationship - while his sister Gemma, 20, was maid of honor.
His new stepfather helped raise the 'Little Things' hitmaker from the age of seven following Anne's split from his biological father.
In the past, Harry has described his mother as one of his closest friends and admitted only she has been told about his love live.
He has admitted: "She knows the truth."