Birthday Suit? John Mayer Dresses Like Old-School Granny To Celebrate 40

John Mayer, 40, was spotted arriving at the Rio de Janeiro airport ­– on his 40th birthday – dressed like an old-school granny, RadarOnline.com has learned. The “Gravity” singer was accompanied by a mystery woman as he landed in Brazil in head-to-toe floral. The musical hunk sported bright red slippers that matched with his date’s fiery red bag. What was Mayer thinking? Click through to see the bizarre photos.

As RadarOnline.com readers know, Mayer dated pop princess Katy Perry, 32, for five years on and off before she found love with Orlando Bloom, 40.

Perry previously ranked him as her number one sex partner, when comparing him to Bloom and ex Diplo, 38.

When they were together, Mayer and Perry were hot and heavy, sometimes even sneaking into secret hotels rooms at the crack of dawn.

He even reached out to her to “make sure she was okay” after he heard about her breakup from Bloom.

Earlier this year, Mayer even made a very public plea for his ex, admitting that his heartbreaking single, “Still Feel Like Your Man,” was all about her.

“Who else would I be thinking about?” he said during an interview with the NYT. “And by the way, it’s a testament to the fact that I have not dated a lot of people in the last five, six years. That was my only relationship. So it’s like, give me this, people.”

Added Mayer about his feelings for Perry: “There were times when tears came out of me, and I went, OK, John, this is not about an on-again, off-again relationship. This is something more profound.”