It was a special occasion for Jessie, who was invited to perform at the musical extravaganza to mark Veterans Day in support of the US Armed Forces.
The 26-year-old showed off her slender figure in a black patterned jumpsuit, which she teamed with black ankle boots.
Jessie was joined on stage by American Idol and Dreamgirls star Jennifer Hudson. The pair performed a duet of David Guetta and Sia's 2011 hit 'Titanium' to massive crowd at the famous National Mall.
Other performances on the night came from Rihanna, Carrie Underwood, Eminem and Dave Grohl.
After her performance, Jessie was pictured in deep conversation with actor and musician Jamie Foxx, and the pair later cuddled up for a photo.
Jessie later told fans on Instagram: "Last night was a moment I will never forget. Representing my country the UK in paying respect to every man and woman who has and does serve for their country, the USA. The strength and courage you have is undeniable. The feeling of unity in the crowd was overwhelming.
"Thank you for allowing me to be a part of your Veterans Day. I seriously salute you. May God continue to watch over you all. ConcertForValor #WashingtonDC."
Last week, former Voice UK star Jessie confirmed that she was in a relationship with US R&B singer Luke James.
Jessie, who has previously kept her quiet life private, explained: "I've realised I can't experience like everyone else if I hide it. I'm famous, it's never going to stop. I'm happy that I'm able to share my life."
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