ListBoxItems background the same as ListBox ItemsSource

I have a WPF ListBox ItemsSource that's bound to an ObservableCollection<string>. The listbox values are:

Blue, Red, Green.

I am wanting the Item's background color to match it's value. For example, I want the Blue Item's background color to be Blue, Red to Red, and so forth. I cannot figure out a way to change each ListBoxItem since I'm using an ItemsSource. How can I bind the ListBoxItems background color to these respective values?

Thank you in advance!!!