Kate Rusby may be out of step with the experimental folk scene, but she has retained an impressive following during her two-decade career. On stage at a packed Festival Hall, she announced with a giggle that her new album, 20, is already a bestseller. This was the live celebration of her "20 years of music making", and, as on the album, she was joined by a celebrity cast helping to rework her back catalogue.

By the end of the evening there were 19 musicians on stage, with a string quartet and American banjo star Ron Block among the guests who had mostly added respectfully minimalist backing vocals.

Rusby has succeeded thanks to her exquisite, pure and breathy voice  and skill in writing or choosing her material. As ever, she was at her best with intimate, often mournful songs with strong melodies, from the banjo-backed The Mocking Bird to the drifting Planets in which she was joined by the Texas star Sarah Jarosz to the lullaby Sho Heen, now a duet with Eddi Reader, or Bring me a Boat, with Declan O'Rourke quietly joining in. Mysteriously, she ignored her finest weepies, Wild Goose and Who Will Sing Me Lullabies, but did include the upbeat but twee Awkward Annie.

It was all classy and pleasant but predictably lacking in noise – at least until Rusby left the stage. Suddenly, there was a furious workout featuring duelling banjos from Block and Damien O'Kane and inspired mandolin from Jarosz. This was a seriously impressive backing band.

What have you been to see lately? Tell us about it on Twitter using #GdnReview