Panetta, 74, a Catholic, sat Wednesday in a front row seat reserved for dignitaries as he listened to Pope Benedict XVI's address to a weekly general audience, The Washington Post reported.
Panetta and three of his military aides then lined up to meet the pope and get his blessing, the Post reported.
"Thank you for helping to keep the world safe," the pontiff said to Panetta, to which the defense secretary replied with the request, "Pray for me."
The papal visit occurred during Panetta's tour of European capitals to meet with NATO allies, the newspaper said.
Celebrity Families of 2014 [PHOTOS]