Ronson, 36, who produced the late singer's Back To Black album, has previously said that the tragic singer was 'like a sister', and made sure that she was remembered when he married French model De La Baume in the South of France on Saturday.
'Amy was a great friend of both Mark and Josephine and they would have been thrilled to have her with them at their big day, but sadly it wasn't to be,' a source told Us Weekly.
'Amy would definitely have sung one of her hits at the wedding if she were still alive, as she meant to much to both of them. Her death devastated the pair of them.'