United Kingdom, April 15 -- Billy Crystal has described Rob Reiner's death as a "profound loss for humanity".

The 78-year-old actor grew emotional as he discussed the passing of his close friend and his wife Michele Singer Reiner - who were killed in December - and admitted there have been multiple times since the tragedy that he's gone to call the director for a chat.

Speaking on The Late Show with Stephen Colbert, Billy - who has two daughters with wife Janice - described Rob as "hilarious, devoted, [and] opinionated in the best way" and someone who was always "fighting for our truth, for our country."

He added: "[He had] the greatest comedy taste. We could talk about everything. He was an uncle to my kids . There's so many moments ....