He may be a world-famous rock star, but Billie Joe Armstrong is a man of the people, too.

Okay - so back in 1996, Green Day arguably weren't the huge band that they are today - but with albums like 'Dookie' and 'Insomniac' under their belts at that stage, they were pretty popular.

A video that the 24-year-old Armstrong sent to a fan back in 1996 has resurfaced on Reddit (via her husband), and it'll put a smile on your face.

The fan, who was 15 at the time, sent Armstrong various letters in the post. When he tried to call her to say thanks, she assumed that it was someone pranking her and hung up on him - twice. She even hung up on his wife, Adrienne, who also tried to convince her that it was real - so he decided to make a video to prove that it was really him.

The below video, which shows Armstrong holding up the various letters and cards that the fan had sent him, is really quite a sweet gesture.