Mayer stopped by the talk show Sunday to celebrate with other close friends of Cohen's and a special happy birthday phone call from Dolly Parton.
Cohen is a big fan of Ross and "It's My House" is one of his favorite songs by the singer.
"I have done nothing but learn that song in the last 48 hours. I have ate, breathed and slept 'It's My House,' and I am now a fan of that song," Mayer said after performing an acoustic version of the track.
Mayer also wished Cohen a happy birthday on Instagram alongside a photo of the pair together.
"Happy 50th Birthday @bravoandy! It's been about 30 minutes since I started writing this caption. Congratulations, I have no words. You've done it. Can't find em right now. They're all scattered in a flurry of love and memories OH HERE THEY COME - in conclusion, I love you, and you are such a special person that I'm sure you are known throughout the universe. See you tonight," the muscian said.
Mayer recently released a comedic music video for his latest single "New Light."
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