The rocker jokes that he expects some "invasive tests" to accompany his upcoming 30th birthday

By Tim Nudd
January 26, 2007 02:40 PM

John Mayer feels secure about his music career – but maybe a little less so about his age and his comedy skills.

Responding to questions from a contestant on the reality show I’m From Rolling Stone, Mayer jokes that turning 30 this coming October will be rough.

“There are lots of very invasive tests that doctors like to administer to men in their 30s,” he says. “These tests usually result in a ride home with the radio off and very little blinking.”

The wisecracking singer has also been working on his career as a standup comedian, and has performed several times at New York’s Comedy Cellar.

Asked to describe the first set where he bombed, Mayer replies, “You mean ‘set’ as in just one? I’m not done bombing. I’m still clearing out a life’s worth of ‘Is that funny?’ To which the answer is usually ‘at least not the way you said it, it’s not.’ ”

Mayer broaches the subject of his relationship with Jessica Simpson obliquely. When asked if he has “ever purchased a Jessica Simpson album,” Mayer replies: “I listen to most new music released every week.”

Mayer and Simpson spent time together in Miami this week. They have been linked on and off since the summer.

In terms of his music career, Mayer says he’s in a groove – fans “come and go” he says, and he’s “okay with that.” But don’t expect him to open up about his celebrity in a song anytime soon.

“I refuse to ever write a song about ANY trappings of fame,” he says. “That’s like your head crowing inside your ass, only set to music. Lots of people think “Vultures” is about fame and the entertainment industry, but it’s not. It’s more about where my confidence comes from.”