The visit to Queen Elizabeth’s Grammar School and Banovallum School followed an invitation by the Horncastle and Louth MP Victoria Atkins.
No details of the visit were announced beforehand and requests for interviews via Ms Atkins’ office were turned down.
The Horncastle News first revealed details of the pioneering partnership between the two schools as part of the Horncastle Umbrella Trust.
It followed Banovallum’s successful move to Academy status.
The two schools have retained their own independence but work together on several schemes - including the purchase of new equipment.
It is widely expected the partnership will become even closer over the coming months.