The real reason Katy Perry and Russell Brand split?

According to Us Weekly, Perry's reluctance about starting a family was a "sore spot" for Brand, who filed for divorce after just 14 months of marriage last December.

"[Russell] feels there's no point in being married if you don't have kids," an unnamed source told the magazine, adding that, at 37, the comedian is "is ready to move on."

Perry's new 3D concert film, Katy Perry: Part of Me," adds fuel to the speculation. According to Us, in one scene, the 27-year-old popstar receives a text from Brand that jokingly mentions baby names. Minutes later, Perry reportedly says to the camera: "A baby can't have a baby -- and I'm still a baby."

This isn't the first report of a domestic disagreement potentially causing the couple's split. Almost immediately after the breakup was announced, a source told British tabloid The Mirror that, "[Brand] wanted [Perry] to stay at home, do the whole Hollywood housewives thing. But that was never going to happen for Katy, she loves her singing career."

Perry and Brand may have even alluded to the reported dispute themselves in separate, pre-split appearances on "The Ellen DeGeneres Show." In November 2011, shortly after the pair celebrated their one-year anniversary, Perry told the talk show host that she believed having children was "one of the reasons you get married," but admitted that she wasn't "sure it's time yet." A month later -- and mere weeks before he filed for divorce -- Brand was quizzed on the subject of babies during his appearance on the show. "I would like one," Brand replied. "I love those little babies in the beginning... They're so lovely in that bit."

Here, a look back at Brand and Perry's one-year marriage:

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  • 'Heaven' Black Tie Gala

    Singer Katy Perry and comedian Russell Brand attend The Art of Elysium's 3rd Annual Black Tie Charity Gala 'Heaven' on January 16, 2010 in Beverly Hills, California. Photo by Jason Merritt/Getty Images

  • 52nd Annual GRAMMY Awards

    Comedian Russell Brand and singer Katy Perry arrive at the 52nd Annual GRAMMY Awards - Salute To Icons Honoring Doug Morris held at The Beverly Hilton Hotel on January 30, 2010 in Beverly Hills, California. Photo by Larry Busacca/Getty Images for NARAS

  • 52nd Annual GRAMMY Awards

    Singer Katy Perry and comedian Russell Brand in the audience during the 52nd Annual GRAMMY Awards held at Staples Center on January 31, 2010 in Los Angeles, California. Photo by Larry Busacca/Getty Images for NARAS

  • 2010 Vanity Fair Oscar Party

    Singer Katy Perry and actor Russell Brand arrive at the 2010 Vanity Fair Oscar Party hosted by Graydon Carter held at Sunset Tower on March 7, 2010 in West Hollywood, California. Photo by Pascal Le Segretain/Getty Images

  • 'Get Him to the Greek' Afterparty

    Singer Katy Perry (L) and actor Russell Brand appear at the afterparty for the premiere of Universal Pictures' 'Get Him to the Greek' at the Greek Theater on May, 25, 2010 in Los Angeles, California. Photo by Kevin Winter/Getty Images

  • 'Get Him To The Greek' Premiere

    Actor/comedian Russell Brand and singer Katy Perry arrive at the premiere of Universal Pictures' 'Get Him To The Greek' held at the Greek Theatre on May 25, 2010 in Los Angeles, California. Photo by Kevin Winter/Getty Images

  • MTV Europe Awards 2010

    Katy Perry (L) and Russell Brand attend the MTV Europe Awards 2010 at the La Caja Magica on November 7, 2010 in Madrid, Spain. Photo by Ian Gavan/Getty Images

  • 'The Tempest' Premiere

    Singer Katy Perry and actor Russell Brand arrive at the premiere of Touchstone Pictures and Miramax Films' 'The Tempest' at the El Capitan Theatre on December 6, 2010 in Los Angeles, California. Photo by Frazer Harrison/Getty Images

  • 53rd Annual GRAMMY Awards

    Singer Katy Perry and actor Russell Brand arrive at The 53rd Annual GRAMMY Awards held at Staples Center on February 13, 2011 in Los Angeles, California. Photo by Jason Merritt/Getty Images

  • 'Arthur' Premiere

    Russell Brand and Katy Perry attend the European premiere of Arthur at the Cineworld O2 on April 19, 2011 in London, England. Photo by Dave Hogan/Getty Images

  • 2011 MTV Video Music Awards

    Singer Katy Perry (L) and husband Russell Brand arrive at the 2011 MTV Video Music Awards at Nokia Theatre L.A. LIVE on August 28, 2011 in Los Angeles, California. Photo by Jason Merritt/Getty Images

  • 'Change Begins Within' Benefit

    Singer Katy Perry (L) and actor Russell Brand attend the 3rd Annual 'Change Begins Within' Benefit Celebration presented by The David Lynch Foundation held at LACMA on December 3, 2011 in Los Angeles, California. Photo by Jason Merritt/Getty Images