Age ain't nothin' but a number and that's especially true when it comes to Betty White.
"The issue of her being 91 doesn't exist for me," Lily Tomlin says in the video above. "I don't think of it, I can't imagine that she's 91. It just doesn't compute. To me, Betty is ageless. She could be as young as 30, I don't know how old she is. She's a puzzle and a miracle."
The "Nine to Five" actress is taking part in NBC's "Betty White's 2nd Annual 90th Birthday Special" airing on Tuesday, Feb. 5 at 8 p.m. EST. In addition to Tomlin, Bill Clinton, Vicki Lawrence, Whoopi Goldberg, Bill Cosby and more celebrities will honor White during the NBC telecast.
Watch the video above for more from Tomlin.