While Jessica Alba would no doubt make that sundae quite tasty, I will one up you with Keira Knightly (think Pirates of the Caribbean, not her weird modeling stuff).
Jessica Alba is like putting on a little more toppings, while Keira Knightly is like adding another gallon of ice cream, chunks of brownie, 3 different types of dark cocoa syrup (65%, 85% and 95%), bananas, strawberries, pecans, some glow sticks, homemade whipped cream and edible fire.