Ipswich singer Caswell has just experienced the most “amazing day of her life” after performing to 40,000 people at Chantry Park and hanging out with Ed Sheeran in her dressing room.
"I met him several times on Monday, but the first time was hilarious," laughed Caswell - who won a national competition organised by Hoax to support the Suffolk superstar on stage at the final night of his homecoming gigs.
"I had just had my hair and make-up done, and I wanted to get dressed quickly because of how hot it was in the cabins which didn't have any fans or anything.
"The band and I were in the middle of getting changed and there was a knock on the door - and it was Ed - he basically saw us all getting changed," laughed the former BRIT school student, who crafts a flavour of neo-sound, downtempo electronica and elaborate pop.
"He was like 'Oh my god I'm so sorry'", explained Caswell, who says he was just coming in to show them the jacket that Lewis Capaldi had made him with his face on it.
Caswell grew up in south London with her then punk rocker, now vinyl dealer mother. With the family influence and a godfather who was a buyer for HMV, she grew up emersed in music - and after this weekend she has just developed a hunger for more.
She said: "The show was amazing, it really couldn't have gone any better.
"There were such great vibes for his homecoming gigs, and it was much more relaxed than Reading and Leeds fest which were just manic."
Caswell is used to performing on big stages, having performed at Latitude festival last year - but she said that the stage and the sound was "epic" at Chantry Park.
"I was so nervous at Latitude last year," she explained. "But before the set on Monday I spent about five or 10 minutes on the side stage to see the audience size and to calm my nerves.
"I wanted to do my best and have no regrets - and I can really say that I gave it all I had.
"I think I was so ready to go because when you work so hard for something you don't want to mess it up."
Caswell is a huge fan of Ed and says the opportunity he has given her is an absolute life-changer.
Speaking of the Castle on the Hill singer, she said: "Everyone says how much of a nice guy Ed is, and they are right. He is so down to earth and so aspirational.
"After our set he sat down with us and said he really enjoyed our performance, which was great.
"He is where he is because of how inspiring and hardworking he is. He has built this tour family of incredible people - there was such a great community feel backstage."
Caswell, whose first name is Kristin, was able to take in 10 people to help her out on the day - which she says is very different to her usual gigs, where she and the band bring all the kit themselves.
When asked what the future holds, Caswell replied: "Who knows if my plans might change, I hope this opens up more opportunities for me, but I also know I have to put in the work and make things happen.
"Being signed is the end goal, but I want the deal to be right for me so for now I'm focussed on building a label for myself.
"I'm going to keep gigging, I'm planning a few tours, but mainly I want to find some time to write."
You can read more about Caswell and her experience in the Hoax competition here.
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