C# – Visual Studio 2013 ADO.net entity model does not have Oracle data source

I've just installed visual studio 2013 and tried to setup Entity framework to access an oracle database.

I click on new ADO.NET entity model, then Generate from database, but on the data connection screen when I click "New Connection" I don't get oracle appearing the list of datasources. I only get two SQL server options.

Do I need to install something extra to get this to work?

The Oracle data source appears in my 2012 version of visual studio that I've got installed on the same machine, so not sure why it doesn't work in 2013.