Jack Johnson was still a few hours away from Manchester, Tenn., to play a surprise set at Bonnaroo with his Brushfire Records act ALO on Thursday night (June 13) when he got the call. Mumford & Sons had just canceled their headlining Saturday night set, and might he like to take it over?

Though a counter-offer was also in the works with Darius Rucker, according to Superfly president Jonathan Mayers, Johnson quickly accepted the offer and canceled a planned visit to Fuse's Waffle House coverage at noon to appear at a quick press conference -- not to mention play a quick set that included new single "I Got You" from his upcoming album "From Here To Now To You."

Jack Johnson and manager Emmett Malloy, co-founder of Johnson's Brushfire Records, take a breather after announcing a last-minute Saturday night headlining set.

Johnson swung by Billboard's press tent shortly after the press conference with manager Emmett Malloy, and talked about survival tips for Bonnaroo -- having previously played in 2003 and 2008, the latter of which he headlined. Considering his last Bonnaroo set included a guest appearance from Eddie Vedder, might Johnson have some other surprises in store? Just a confirmed duet with ALO for now, he said, and more stripped-down arrangements to accommodate the largely acoustic vibe of the new album.

Elsewhere, Billboard.biz caught up with Passion Pit's Michael Angelakos after he spoke on a press-tent panel with Matt & Kim, Ed Helms, John Oates and Nicki Bluhm. Angelakos is one of the hardest-working musicians on the festival circuit lately, having wrapped the band's first arena tour earlier this year when it sold out venues like Madison Square Garden and played shows at South By Southwest, Coachella and Sweetlife.

(From left) Nicki Bluhm, John Oates, Ed Helms and Passion Pit's Michael Angelakos talked touring, festival etiquette and YouTube in a Friday afternoon panel.

Despite the band's breakneck schedule, Angelakos keeps his falsetto-heavy vocals in check with a mix of sleep, water and minimal drinking. "I've also been doing it enough that my voice has developed new muscles, so it's easier now for me to that register," he told Billboard.

Some industry execs were still getting to the festival grounds by Friday afternoon, especially those traveling from New York where they experienced flight delays due to Thursday's rain. Those spotted at the festival already include Red Light's Coran Capshaw, Superfly's Chad Isaaq and INDmusic's Brandon Martinez.

Matt (in sunglasses) and Kim of Matt & Kim catch up with Ed Helms following a press conference in the media tent.