Question for the singers and music aficionados

[Barefootgirl]

I was watching an old rerun of The Ed Sullivan Show (don't judge) and Johnny Mathis and The Lennon Sisters did a song called Johnny One Note. Johnny Mathis holds this note for 1 minute 28 seconds. Pretty impressive if he actually did it. I saw it with my eyes and heard it with my ears but the Jersey in me says nah it's got to be more to it. So my question to you is, is it possible to hold a note that long? How did he do this?

 

[NorthernLight]

Apparently Johnny Mathis was classically trained to sing opera, etc. So I guess he knew some techniques.

I also read something about opera singers using "air compressors." I can't imagine how that would work.