Ms. Amy Birks and folky proggers Moulettes are the final additions to the 2020 Summer's End line-up.
The join a bill that also features Antimatter, Pallas, Gungfly, Cosmograf, Jump, I Am The Manic Whale, Cyan featuring Rob Reed and Peter Jones and Lesoir.
"We are thrilled to announce a full band set from the amazing Amy Birks," the organisers tell Prog. "Amy has just released her debut solo single Jamaica Inn, following on from the success of her former band The Beatrix Players, and will tour next year playing both solo and full band sets.
"Prog Magazine have called Moulettes 'Huge, complex and compelling. One of the most thrillingly nimble musical ensembles the UK has produced in decades.' We definitely agree - they are one of the most exciting new prog bands to emerge in many years."
Next year's Summer's End takes place at Chepstow Drill Hall from October 1-4. Sponsor and weekend tickets are available from the Summer's End website.
Day splits and day tickets will be announced in January 2020, as well as the line up for Thursday 1st October.