Fergie  vienna life ball Kelly Osbourn

A heavily-pregnant Fergie and her pal Kelly Osbourne hosted the 2013 Life Ball Saturday in Vienna, Austria. The 31-year-old singer even performed during what is Europe's largest AIDS fundraiser.

In addition, both ladies judged the event's Voguing Ball Contest -- fun!

And Fergie's baby bump got a little love from Life Ball spokesperson, former President Bill Clinton. We bet it'll be good luck!

Fergie  Bill Clinton vienna life ball