The royal arrived to the service at St Luke’s Church in Chelsea without his fiancé, Meghan Markle, who he’s set to wed next May.
However, one of Prince Harry’s former loves was in attendance, in the form of Cressida Bonas.
Harry and blonde actress Cressida dated for two years, before they split in 2014.
The 28 year old arrived to the carol concert linking arms with her mother, Mary-Gaye Curzon, as she stunned in a stylish ensemble.
Dressed in a black dress, she amped up the fashion factor with a deep blue suede coat, clinched in at the waist with a leather belt.
Other recognisable faces at the service included Kate Middleton’s sister Pippa Middleton and their mother, Carol.
Prince Harry and Meghan Markle hold hands as they arrive in Nottingham for their first royal commitment as fiancé’s [PA]
28 year old Cressida – also known as Cressy – is a descendent of King Charles II, and is daughter to entrepreneur Jeffrey Bonas and Lady Mary-Gaye Curzon.
The star found fame through her acting and modelling career, which included modelling for Burberry and Mulberry.
The pair met because Cressy is good friends with Harry’s cousin Princess Eugenie.
Most recently, the star appeared in a music video for James Arthur’s song, Naked.
While Cressida has not said anything publicly about Meghan and Harry’s engagement news, the star posted a quote on her Instagram shortly afterwards, which many believed to be about her ex.
The quote read: “No matter how educated, talented, rich or cool you believe you are, how you treat people ultimately tells it all.”