The 51-year-old model and special constable was on duty on The Mall for the funeral procession.
The model and TV presenter is a volunteer police officer and marshalled the crowds outside the RAF airbase where Queen Elizabeth's coffin landed in London.
The rocker and his spouse spoke about her experience with the menopause on 'Loose Women'.
The TV star shared how husband Rod Stewart had been supporting her through her difficulties.
The 50-year-old model has received her warrant card and police badge after qualifying as a Special Constable.
The model recently shared a picture of her and Sir Rod with his first wife and two ex-girfriends as they united to celebrate daughter Kimberly's 40th birthday.
The model wife of Sir Rod Stewart broke down in tears as she recalled her experience of being bullied at school.
Viewers have praised Loose Women star Penny Lancaster's resolve after she was threatened with being stabbed while appearing on a new fly-on-the-wall documentary show.
Sir Rod Stewart has been forced to apologise after he was filmed appearing to re-enact an Isil-style beheading while in the middle of the desert.