After a few years of mixing major EDM acts into the headliner rotation, it looks like this summer's Lollapalooza might lean a bit more heavily on guitars and, well, banjos. Though organizers have not yet officially announced the lineup for the annual rock bacchanal by the lake in Chicago, the Chicago Tribune reported that Mumford & Sons and Vampire Weekend are among the acts tapped to headline the fest, which takes place on August 2-4 in the city's sprawling downtown Grant Park.

Citing multiple unnamed industry sources, the paper also reported that Phoenix and the Killers are expected to perform, along with the National and the reunited Postal Service. A spokesperson for Lollapalooza told MTV News that the news could not be confirmed at press time and that the official lineup is not expected to be released until April 9.

Lineups for a number of major summer festivals, including Coachella and Bonnaroo, often leak before their official announcement and predictions are sometimes dead on, or, just as likely, totally off the mark.

The Lolla lineup has drawn even more buzz since the launch of competing Twitter accounts last month that have both claimed to have inside scoop on this year's performers. @TheLollaLeaker and @AgentofLolla have had a spirited back-and-forth about their allegedly exclusive line on who is playing the fest, which draws more than 270,000 fans.

@AgentofLolla went so far as to post what is allegedly a screen grab of a lineup, which included the above-mentioned bands, as well as the Flaming Lips, MGMT, Kendrick Lamar and Skrillex.

You might recall that last year Lolla co-founder and Jane's Addiction singer Perry Farrell [article id="1679400"]lashed out[/article]
 at an anonymous Twitter leaker who claimed to have the roster for the 2012 fest. As it turns out, the party crasher was way off the mark with a number of their predictions (sorry Korn, Missy Elliott, Beck and Sonic Youth).