A two-day auction of George Michael’s art collection earned over $15 million, which will be used toward the late singer’s philanthropic efforts.

During his lifetime, Michael amassed dozens of works by contemporary British artists – like Damien Hirst, Tracey Emin, Sarah Lucas, Michael Craig-Martin and Marc Quinn – who formed the Young British Art movement.

“Through visits to galleries and artists’ studios, [Michael] developed friendships with many of the YBA artists whose work he deeply admired,” Christie’s auction house in London said of Michael’s collection, which 12,000 people visitors viewed at a pre-auction exhibition.

Two works by Damien Hirst from Michael’s collection – The Incomplete Truth and Saint Sebastian, Exquisite Pain – alone sold for a combined $2.3 million. A Tracey Emin neon titled George Loves Kenny received a high bid of $461,000.

A pair of commissioned works also sold for six figures: Michael Craig-Martin’s Commissioned Portrait Untitled (George) – a wall-mounted LCD monitor/computer with integrated software that displayed a color-changing portrait of the singer – sold for $231,000, a record for the artist, while Jim Lambie’s Careless Whisper, named after the Wham! song, $232,000, nearly 10 times its pre-auction estimate.

An additional $332,000 from the sale of catalogues and limited edition tote bags will also go toward charity.

“Philanthropic work was hugely important for George during his lifetime and it was his wish that this work would continue after his passing,” Michael’s trustees said following the auction.