Michael Buble says working with Willie Nelson was 'greatest moment' of his life

April 19 (UPI) -- Michael Bublé says working with Willie Nelson was the "greatest moment" of his life.

The 46-year-old Canadian singer discussed working with Nelson, 88, and Paul McCartney, 79, on his album Higher during Monday's episode of Watch What Happens Live.

Bublé and Nelson recorded a version of Nelson's song "Crazy" for Higher. On WWHL, Bublé was asked about the experience and if he got "higher" while working with Nelson, a marijuana enthusiast.

"Number one, it was the greatest moment of my life, because he's been my hero forever," Bublé said.

"Number two, god bless Willie, and I don't need anyone to help me get high," he added.

Bublé also confirmed that McCartney produced the album.

"It was amazing," Bublé said of working with McCartney.

"Have you ever seen Bram Stoker's Dracula with Keanu Reeves? When Dracula always floats in, it looks like he's on rollerblades? Paul, literally help him, I think he might be part vampire because he just sort of like slides ... he's so cool," he added.

Bublé released Higher in March. The album features the singles "I'll Never Not Love You" and "Higher."