If Kelis and Robyn aren't already best friends, they should be. Even though the dance-pop divas came of age on opposite sides of the Atlantic - one in New York, the other in Sweden - they have a lot of things in common.
For instance, both showed up to their sold-out co-headlining gig at the 9:30 Club on Monday night armed with heavy percussion, booming dance beats, and gut-rattling bass. And both came toting a strong, thoroughly female pop-sensibility - big emotional hooks infused with pleasure-friendly feminism. "I've got some news for you," sang Robyn. "Fembots have feelings, too."
In a summer where Lilith Fair - the traditional ladies-first summer music fest - is sagging from soft ticket sales, Kelis and Robyn are doing their part to keep big-tent sisterhood alive.
Except that the audience was mostly male. The floor was a rowdy, sweaty, brodeo, with a XY-to-XX ratio no better than 3:1. There were gentlemen from all walks of life - guys in buttoned-down office garb, guys in Hawaiian shirts, and even a few men trussed up in headdresses. Kelis is right; her milkshake really does bring all the boys to the yard.
Robyn and Kelis' similarities run deeper than their current stage set-up, though. Both are pop music lifers who cut their teeth on R&B and spent years being passed through the hands of various producers. Both have largely put that time behind them and are entering their 30s with a new image and a focus on straight dance floor uplift.
But there are slight differences in their musical reference points. These days, Kelis is a Diana Ross woman. Robyn, who is shockingly tiny in person, is more of an anime-pixie take on Annie Lennox.
Performing in a silver wig alongside a drummer and two DJs, Kelis' set was an hour of unrelenting bass-oomph drawn mostly from her latest record, "Fleshtone." Arranged mixtape-style, the music shifting seamlessly from song to song, frequently after only one verse, with a few hooks borrowed from her peers (Ol' Dirty Bastard's "Got Your Money" was a nice surprise). Her biggest hit, "Milkshake," was given a disco facelift - set to a straight house beat and mashed up with Madonna's "Holiday." Kelis may have come up as an R&B artist, but she might have been ignoring her calling. She makes an even better disco diva.
Robyn's music is more diverse - bouncing from '80s new wave, dancehall, to house-music, sometimes during the same song. Accompanied by two drummers and two keyboard players, the Swedish singer performed an hour-and-a-half of ebullient pop. The band was great, but if you weren't looking hard, you might have missed them. Despite her size, Robyn has an overwhelming stage presence. She's in constant motion - jerking, jiving, and popping all kinds of alien-looking Eurovision Song Contest-worthy moves. She has pretty great pipes, too - her voice loaded with enough raw emotion that it sounded human even when the robot effects were switched on. Kelis has more recognizable hits, but when it come to the live show, Robyn has her beat.
It's hard to tell just how friendly Kelis and Robyn really are, though. The American and Swedish dance-pop divas announced the tour, dubbed "All Hearts," via Twitter conversation - as if the whole concept was casually put together with a latte in one hand and an iPhone in the other. But Monday night's performance had little in the way of inter-artist rapport - there were no walk-ons, no duets, not even an end-of-set hug. As much as they have in common, the joint bill is partly a marriage of convenience, a temporary alignment against mega-fabulous behemoths like Lady Gaga.
But why not keep a good thing going? Robyn and Kelis should stick together.