The 'Dragonball: Evolution' actress says the couple parted ways around two months ago, after almost a year of dating, but they remain 'very close friends'.
The pair started dating after meeting through social networking site twitter at the end of 2009, shortly after the breakdown of Emmy's year-and-a-half marriage to music executive Justin Siegel.
Emmy explained: "I was on tour with the band this summer. They invited me actually on twitter. That's how we met - on a dare."
The 22-year age gap between Emmy and 46-year-old Adam raised eyebrows at the time, but the 24-year-old actress said of the dreadlocked star: ' get why chicks dig him.'
'Mr Jones' singer Adam has an impressive list of A-list ex-girlfriends which reportedly includes Jennifer Aniston, Courteney Cox, Winona Ryder, Nicole Kidman and Christina Applegate.
Although her relationship with the musician is over, Emmy should have no problem finding another boyfriend, especially as she is now far more confident with her body and looks.
She said: ' used to be an artsy, quiet, kind of chubby kid ' which no one believes - but now I'm really comfortable with my body and my sexuality. I can be naked with the lights on.'
The actress will next star in a US TV remake of British comedy drama series 'Shameless', which will begin in January next year.