The couple have been together for almost two years and reports recently suggested they might be about to move in with each other after Cressy was given the seal of approval from Royal security guards.
Harry also kept it casual with a blue check shirt and jeans.
According to The Metro, Cressida playfully heckled Prince Harry when he took to the stage and joked and apologised to anyone expecting another famous Harry (Styles, fyi)
It's a rare public display of affection from the couple who were also pictured together earlier in the week as they left The Ivy.
Let's look back at Cressie's style...
More:Have You Seen?
Suggested For You
SUBSCRIBE AND FOLLOW
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements.Learn more