Johnny Lewis
(Dated 2005-2006)

The troubled "Sons of Anarchy" actor and Perry broke up in 2006, before her singing career took off. Tragically, Lewis died in September 2012 after the 28-year-old fell from a rooftop; his untimely passing reportedly left Perry "devastated." Lewis partially inspired "The One That Got Away," the somber single from "Teenage Dream."

Travie McCoy
(Dated Summer 2007-December 2008)

When Perry first broke big with "I Kissed a Girl," she was busy kissing Travie McCoy, the frontman of Gym Class Heroes who later scored a solo hit with "Billionaire." The on-and-off relationship ended at the end of 2008, when McCoy posted on his blog confirming the split on New Year's Eve. "Circle The Drain," from Perry's blockbuster 2010 album "Teenage Dream," reportedly touches upon her first stint as part of a power couple.

Josh Groban
(Rumored to date in early 2009)

After Perry and Travie McCoy split, rumor had it that the "Waking Up In Vegas" singer was spending time with Josh Groba, who was still riding the success of his "Noel" holiday album. Although reps for the artists denied the coupling, Groban admitted last year, "We might have skated on the line of dating." Perhaps that makes Groban the "Dark Horse" in Perry's dating history?

Russell Brand
(Married October 2010, Divorced December 2011)

After forming a relationship upon a fortuitous meeting at the 2009 MTV Video Music Awards, Perry and "Get Him to the Greek" star Russell Brand became involved in a whirlwind romance that led them down the aisle barely a year after they started dating. Sadly, the marriage ended after 14 months, with Brand filing for divorce days before the end of 2011. Multiple songs on "PRISM" nod to the failed marriage, including the emotional closer "By The Grace of God."

Baptiste Giabiconi
(Rumored to date in March 2012)

Months after Perry split with Russell Brand, she graced tabloid covers alongside French male model Baptiste Giabiconi, whom she had been friends with for years. The singer nipped those dating murmurs in the bud, though, stating on Twitter that she was "single and satisfied."

Robert Ackroyd
(Dated Spring 2012)

Unlike the Baptiste Giabiconi rumors, there was some truth to the chatter that Perry dated Florence + The Machine guitarist Robert Ackroyd during the first half of 2012. Although she said to USA Today in July 2012 that it was "not even appropriate to label" the pair as a couple, Perry said, "There are times I go out and meet people and flirt, but it's not really appropriate to have anything serious."

John Mayer
(Dated August 2012-February 2014)

The relationship between Perry and John Mayer included several twists and turns over a year-and-a-half period, but late last year, the "PRISM" singer seemed thrilled to be back in love with Mayer, whom she called "literally a genius" in her most recent Billboard cover story . That enthusiasm ended just a few months later, however, when the two musical superstar confirmed their split in late February. We can reflect on happier with Perry's song "It Takes Two," on which Mayer plays guitar.

Robert Pattinson
(Rumored to date in summer 2013)

During one of Perry's off-again periods with John Mayer, rumors flew that she was dating "Twilight" star Robert Pattinson, although they mostly proved to be unfounded. The pair took in a Bjork concert together last June, but the following month, Perry confirmed that she had cleared the air with Pattinson's ex, Kristen Stewart, by texting her to tell her that her relationship with Pattinson was platonic.

Diplo
(Rumored to date in April 2014)

The latest reports surrounding Katy Perry's love life involve veteran producer Diplo: both artists were at Coachella, and rumors are swirling that they were soaking in the California sun as more than friends. However, the "Birthday" star recently said on "Jimmy Kimmel Live!" that she is not dating anyone.