Billy Crystal thinks "humour and trust" are the keys to a successful marriage.
The 76-year-old actor - who tied the knot with Janice Goldfinger, 75, in 1970 and went on to have Jennifer, 51, as well as 47-year-old Lindsay with her - admitted that the "respect" he and has wife have given each other over the years has meant they are still together more than half a century later.
