Bleachers frontman Jack Antonoff, whose ancillary titles include Grammy winner, guitarist for the band Fun, and Lena Dunham’s boyfriend (not necessarily in that order), is among today’s most promising songwriters, having worked with Taylor Swift, Lorde, and Sara Bareilles. So it wouldn’t be entirely surprising to see a super successful pop star like Pink in the crowd for his band’s show at Sunset Strip standby The Roxy on Thursday night. But was there more to the singer’s cameo?

While the “official” reason for Pink’s attendance (with longtime manager Roger Davies) is that she and Antonoff are friends, multiple sources tell Variety that the two are currently collaborating on songs that could make her long-awaited seventh studio album, Pink’s first since the double platinum “The Truth About Love” was released back in 2012. Certainly, the combo of Pink and Jack — Pack? — seems perfectly suited for the popularity of staccato synths and soaring vocals in pop music currently, especially on Top 40 radio.

Indeed, Antonoff has proven himself adept at adapting to musical trends, and perhaps there’s no better example of that than Bleachers, where he really gets to wear his influences on his sleeve. So for this “underplay” gig — performing at a 500-person capacity club as opposed to the festivals and amphitheaters the band will hit starting in May (Bleachers is booked by Paradigm and managed by Tyler Childs at QualityCTRL) — fans, friends, family (Antonoff’s dad was spotted beaming from the soundboard) and VIPs (including “Mad Men” star Elisabeth Moss) got to hear them all: guitar solos, sax riffs that nod to the E Street Band, and the sort of choppy keyboards that could have been heard on an early Bon Jovi or Journey record.

The heft of two drummers (a nod to the Grateful Dead?) added to the intensity, while Antonoff’s contagious enthusiasm — bordering on goofiness — riled up the crowd even more as he introduced new songs like “Don’t Take the Money” (written with Lorde) from Bleachers’ forthcoming album, “Gone Now,” due out June 2, and rocked out to fan favorites like “I Wanna Get Better.”

Antonoff admitted more than once that it had been two years since Bleachers last played live, and that the road to “Gone Now” was even longer. What he neglected to share? That the experience of collaboration has only sharpened his skills as a writer and a musician, and the pop world is better for it.