Boasting perhaps the most stellar lineup in its seven-year history, BMI and Billboard's Acoustic Brunch on the lawn of at the Four Seasons kept the mimosas flowing just as steadily as the hit tunes.

American Authors, currently at No. 16 on the Hot 100 and No. 15 on the Billboard 200, led a bill that also included psych-rockers Phox, folk-pop duo Johnny Swim, Australian dance-pop singer Betty Who, Graffiti 6 frontman Jamie Scott, Australian indie-poppers The Kin and British indie-soul singer Bipolar Sunshine.

Each act performed stripped-down versions of their best known songs -- including Johnny Swim's "Heart Beats," Betty Who's viral hit "Somebody Loves You," American Authors' "Best Day Of My Life" and One Direction's "Story of My Life," the latter of which Scott co-wrote with Julian Bunetta and the band for November's "Midnight Memories" (and performed impeccably by himself.)

The brunch is also a routine stop for senior record label, management, publishing and media executives, many of whom kept the Four Seasons lawn as densely packed as ever while stocking up on breakfast tacos, fresh fruit and iced coffee from sponsor High Brew. L.A.-based exec Scott Perry summed up the scene best when he tweeted, "@bmi brunch with a few hundred friends @sxsw"