Ono was given the task of curating this year's (13) Meltdown and attracted stars including Iggy Pop, Patti Smith, and Boy George to the bill of the 10-day event.
Sioux, who famously covered Lennon's 1968 track Dear Prudence during her days as singer with Siouxsie and The Banshees, was one of the many artists who performed on the final night of Meltdown on Sunday, and Ono joined her for a rendition of Walking on Thin Ice, the track she and Lennon were working on the night he was murdered.
Ono later took to Twitter.com to post a photograph of the pair onstage together, along with the message, "The last song of the last night of the Meltdown! Siouxsie and me doing Walking on Thin Ice."
Lennon was assassinated outside his New York apartment building in December, 1980 after returning from a recording studio with Ono.