Laravel query builder: with relationship

I have two tables: dayreport and dayreport_events, with a one-to-many relationship.

class DayreportEvent extends Model
{
    public function dayreport(){
        return $this->belongsTo('App\Models\Dayreport');
    }

In this case I want to query all dayreportevents to get Instances of the DayreportEvent class. But from this instance I want to have access to the Dayreport instance. To avoid an individual database query for each row, I want to use the with() method in the query builder:

DayreportEvent::with('dayreport')->get();

But with this query I get the following error:

Call to undefined relationship [App\Models\Dayreport] on model [App\Models\DayreportEvent].

Why can't I do it like this?

via Chebli Mohamed