SIR Elton John will join British artist pal Tracey Emin to showcase work this summer at a prestigious contemporary art festival in Venice, Italy. John is set to perform at St Marco's Piazza (St Mark's Square) - a ninth century piazza - as part of the waterlogged city's Biennale, a renowned exhibition held every two years. Emin, who is known for her controversial modern installation work, will exhibit at the showcase which began in 1895 and has since grown to be an international event.