Pharrell Williams won't be joining 'The Voice' .

Pharrell Williams

Pharrell Williams

The 'Happy' hitmaker has admitted he won't be signing on to fill departing judge Rita Ora's seat on the BBC talent show or joining rival series 'The X Factor' as he needs time to recover from mentoring on the "intense" US version of the show.

Speaking at this year's Glastonbury festival over the weekend, he said: "I couldn't juggle 'The Voice' back home with 'The X Factor' or 'The Voice' here, it's too intense.

"I need time off after 'The Voice' to decompress, because you give a lot of emotion in giving the best guidance you can."

Although the 42-year-old singer found his time on the show tiring, he would advise all musicians to become a mentor on the talent search and insists the experience has "sharpened" his focus.

He explained to the Daily Star newspaper: "It's sharpened me up as a musician and made me look at music more clearly."

Meanwhile, Pharrell was clearly in high spirits as he invited a swarm of fans up on to the stage with him at Worthy Farm on Saturday (27.06.15) and admitted he loves performing at the festival rain or shine as the crowd gives off a "unique energy".

He said: "I love festivals because you get a unique energy when people enjoy themselves outdoors.

"I was lucky it was sunny, but I love playing in the rain too because the fans stick through it with you and show how much they for you by sticking around.

"That makes me go harder, even if I'm getting wet or worried about catching a cold."