How to add a backslash in an insert query (ex App\User)

I have a specific requirement to run this query directly without using Eloquent ORM

                DB::insert("INSERT INTO projects SET
                    subject_type='App\Project',
                    causer_type='App\User',
                    created_at= NOW(),
                    updated_at= NOW()
                ");

It works but it doesn't add the back slash e.g App\User becomes AppUser. I tried adding two App\\User but it still added as AppUser.

Any ideas how to get it working?

Thanks