How can I find the names and details of clothes worn by celebrities?

[LemonLimeTime]

For example, let's say I wanted to dress like Kurt Cobain for Haloween, and I wanted to buy the same, or a similar outfit to one he wore, where do I research that kind of thing? Like let's say I wanted to dress up as Denzel from Training Day, how do I find out the designer name of the shirt and pants? Please help?! I have searched every combination of words, but all I get is t-shirts with the band name on it! Thanks guys and gals!