Yes indeed both Don Knotts and Andy Griffith are related in real life.
It's been confirmed that Don Knotts and Andy Griffith are actually blood related cousins.
Don Knotss and Andy Griffith were also best friends in real life and on the show and they were also cousins.
Both Don Knots and Andy Griffith made a great pair for actors on the Andy Griffith show.
There could have been no better Barney Fife than Don Knotts in my opinion.