It would seem so from the extract below, but those who frequent the Atlantic will be able to provide actual experience.
Access to Partner airline lounges
In addition to Qantas Club lounges, you can relax in British Airways lounges (Terraces and Executive Club lounges) and American Airlines® Admirals Club lounges.
To access a partner airline lounge, simply present your Qantas Club card or Platinum or Gold Frequent Flyer card at check-in and again with your boarding pass at the lounge reception. You may also invite a guest. Note: both you and your guest must be travelling together and have onward travel that day on a flight marketed and operated by the partner airline whose lounge you wish to visit.***
*** Marketed and operated means a flight operated by the same airline whose flight number appears on your ticket. Includes American Airlines® or British Airways operated flights with a 'QF' flight number on your ticket.
http://www.qantas.com.au/travel/airl...cess/global/en