Oscar-winning actress Julia Roberts is joining a growing list of Hollywood celebrities showing their support of Proposition 87 in California. The ballot measure would raise taxes on oil production to fund alternative energy sources. The Erin Brockovich star visited children at UCLA's Children's Hospital in Westwood, California, on Monday (16OCT06) to make her point. The children she visited were in hospital due to illnesses related to air pollution. The proposition would levy a $4 billion (GBP2.2 billion) dollar tax on oil pumped out of California wells. She said at the event, "California has always seemed to be the free-thinking, forward-moving pioneer of this country. "Well, now, when it counts the most, really to our children, to all of our health and welfare, to our future, let's lead the way. Let's vote yes on Prop 87." Oil producers have so far donated $54 million dollars (GBP30 million) to oppose Proposition 87 arguing that it will raise oil prices.