by invitation
by invitation only

Last year there were about 130 cars, by invitation, in 9 classes.

The guests showed up in some numbers, by invitation, of course.

It was a limited field event, open by invitation only.

They are usually by invitation only, and not all cruise lines offer them.

It was the custom for men to come to the place only by invitation.

This is by invitation, and subject to the behavior of the previous class to visit.

As it has always been, membership is by invitation only.

Private events cannot be found in searches and are by invitation only.

The Club has always admitted new members by invitation only.

All visits are by invitation of the family and on their own terms.