String extension method in Linq query

String extension method in Linq query

How to use string extension method in linq query:
public NewsType GetNewsType(string name)
{
var newsType = db.NewsTypes.FirstOrDefault(x => x.Name.ToFriendlyUrl()
== name.ToFriendlyUrl());
return newsType;
}
Above query "x.Name.ToFriendlyUrl()" is not allowed at the minute. Is
anyone know how to achieve with it.