Carlo Ancelotti insists he could never manage Atletico Madrid or Barcelona out of respect for Real Madrid's rivalry with the two clubs.
The Bayern Munich boss spent two years in Madrid, beating Atleti in the Champions League final in 2014.
And Ancelotti believes that his managerial history means that any return to Spain would have to come at Santiago Bernabeu.
"No, I will never train [Atleti or Barca]," the Italian told Marca. "I respect the history of the rivalry and in the same way, I couldn't train either Lazio or Inter.
"It's my story and respect is very important. I have a lot of respect for Atletico and Barcelona, but I can't train them because I've coached Real Madrid for two years."
Ancelotti will take his Bayern side to Atleti's Vicente Calderon on September 28 after they were drawn together in the Champions League group stage, and he is expecting a predictably frosty reception.
"The reception will be normal for a rival team and a rival coach," he added. "I'll do my job, which is the challenge of winning at the Calderon.
"Things have not gone well for me there before but I want to win with Bayern."