India, June 17 -- While shooting an intense sequence for Season 4 of Reacher, the cast and crew were caught off guard by two unexpected guests. Former US president Joe Biden and his son Hunter happened to stroll into the middle of filming in Philadelphia, turning an ordinary Monday into something far more memorable.

Alan Ritchson, who plays the titular role in the popular Prime Video series, was just wrapping up a scene when black SUVs pulled up near Rittenhouse Square. To everyone's surprise, out stepped the Bidens, prompting cheers and applause from the cast and crew. The moment, which could've easily passed for a movie twist, quickly went viral.

Taking to Instagram the next morning, Ritchson posted several photos with Joe and Hunter ...