Princess Charlene has seemingly charmed Pope Francis during a private call on the pontiff at the Vatican along with her husband, Prince Albert II of Monaco.

Francis was smiling as Charlene knelt before him, grasped the pope's right hand and kissed it Monday.

Both the princess and the pope wore white. Charlene wore a simple, elegantly tailored off-white coat, white gloves and beige high-heeled pumps while Francis wore his usual gown.

The couple didn't bring their 13-month old twins, Gabriella and Jacques, but Francis said: "I will pray especially for your children."

Francis chatted for 20 minutes with the couple on a busy morning that included meetings with a Lutheran delegation from Finland and with the head of the International Monetary Fund, Christine Lagarde.