The 67-year-old statesman issued a playful tweet to living ex-presidents for Presidents Day on Monday, but questioned George W. Bush's lack of social media presence.
"#HowAreYouNotOnTwitter?" Clinton wrote in a hashtag.
Despite their disparate political inclinations, Clinton and George H. W. Bush, No. 43's father, have enjoyed a close friendship since they left their respective presidencies. George H. W. Bush's children even see him as a brother figure, according to Andy Card, George W. Bush's former chief of staff.
"They have become really great friends; in fact almost like family and that's like a jealousy for the rest of the Bush kids," Card told CNN last year. "They think they got this other brother named Bill Clinton. It is a wonderful warm relationship."