George W. Bush explains his fondness for Michelle Obama

Former President George W. Bush and Michelle Obama are surprisingly close considering their political differences, and the 43rd president credits the former first lady's appreciation for his sense of humor as a key reason.

The unlikely pair have often been photographed together during formal events. When Obama embraced Bush at the opening ceremony for the Smithsonian National Museum of African American History and Culture last September, the photo of their warm interaction went viral.

George Bush returns to the political scene

    "When I saw her, it was a genuine expression of affection," Bush told People magazine as he reflected on the moment.

    Former first lady Laura Bush, former President George W. Bush, first lady Michelle Obama and President Barack Obama attend the opening ceremony for the Smithsonian National Museum of African American History and Culture on September 24, 2016, in Washington.

    The former President is back in the public eye to promote his new book, "Portraits of Courage," a volume of his paintings of military veterans.