During May and June of 1944 the Mighty O had the unique experience of being detached to a multi-national force. The Anzio invasion, south of Rome, had occurred four months earlier and still Allies were trapped in the beachhead area. So that naval gunfire could be applied to deeper targets, the French cruiser Emil Vertin and the British AA cruiser Dido, were employed because of their excellent artillery.

The Ordronaux and a sister, USS MacKenzie, would screen for these ships, contributing their fire support as well. Some claim there was a conspiracy in assigning the two American destroyers to this force due to their unique Anglo-French names. Nevertheless, the mixed unit proved to be a effective team.

Ordronaux and Dido cruising off Italian coast in 1944; as seen from MacKenzie DD614.	Looking aft from MacKenzie at HMS Dido with Ordronaux crossing in the distance.
MacKenzie leads Ordronaux in laying a smoke screen for Allied cruisers.