Christina Aguilera, Lana Del Rey play with personas: Perspective When Christina Aguilera declares at the top of her new album, "There's a thousand faces of me," she's exaggerating, but not by much. How many Aguileras have we seen since the onetime "Mickey Mouse Club" member rocketed to superstardom in 1999 with "Genie in a Bottle"? She's been the good girl, the bad girl, the Lady Marmalade; she's gone blond and brunet and purple-and-pink; she's worn long pants, hot pants and no pants at all. And her music has metamorphosed with her, from the tinny teen-pop entreaties of her self-titled debut to the lusty thump of 2002's "Stripped" to 2006's "Back to Basics," a lavish double-disc tribute to old-school jazz, soul and funk. PHOTOS: Christina Aguilera's style through the years In 2010, under threat of being usurped by Lady Gaga, Aguilera attempted yet another makeover with the harshly futuristic "Bionic," but the album tanked (at least by pop-diva standards); its failure was followed by a string of personal and professional troubles, including a divorce, a big-screen dud in the form of "Burlesque" and a public-intoxication arrest that might've been viewed as a boon back in the "Dirrty" days. Yet the singer regained her footing with her role as a judge on "The Voice," and it's the work she's done in that capacity - advising young hopefuls on how to connect with an audience - that seems to have most informed "Lotus," her seventh studio album. That tally, FYI, includes Christmas and Spanish-language discs, further indication of Aguilera's thousand-facedness. Full of collaborations with hitmakers such as Max Martin, Sia Furler and Alex Da Kid, "Lotus" feels like an honest attempt to get back into the mainstream; it forgoes any grand concept that might cloud the music's radio-ready sheen. That doesn't mean she's not still in the business of transformation, though. Aguilera is simply working faster now, adjusting her personality on a song-by-song rather than album-by-album basis. "You thought you'd watch me fade away / When you broke me into pieces," she sings over an industrial-disco stomp in "Army of Me," "But I gave each piece a name." And they're all here: the street-smart sex bomb in "Red Hot Kinda Love," the self-empowered survivor in "Sing for Me," the dance-floor do-gooder in "Make the World Move," which features her "Voice" costar Cee Lo Green. Another "Voice" judge, Blake Shelton, turns up at the end of the album, in the '80s-style soft-rock ballad "Just a Fool." None of these discrete personas impact as powerfully as they did pre-"Bionic," but that's more the result of an altered landscape than of Aguilera's diminished talents. Her singing can still startle, as in the relatively unadorned "Blank Page." On the Hot 100 the album's lead single, "Your Body," sits at No. 75, well behind hits by Rihanna and Kesha, both of whom are operating firmly in a post-Aguilera mode. Serial reinvention is now a beginning, not an end. Maybe that's why Lana Del Rey, who like Aguilera has a new release in stores this week, is clinging so tightly to her chosen narrative: Barely 18 months into her public career, this savvy young chameleon looks determined to play a long game. Del Rey ignited the Internet last year with a homemade video set to her song "Video Games," an alluringly mysterious pastiche of all-American phrases and imagery that's racked up over 45 million views on YouTube but also led to debate over Del Rey's background - specifically, how "Video Games" relates to earlier, more straightforward recordings she'd issued under the name Lizzy Grant. If the preceding paragraph almost put you to sleep, you can't be blamed, as it's difficult to imagine a preoccupation more boring than the authenticity fetish embodied by certain sectors of online music culture. Unfortunately, Del Rey's album, "Born to Die" (which came out in January), turned out to be painfully dull, too: a tantalizing fiction stretched to flavorless lengths. She's much better on "Paradise," a surprisingly strong eight-song EP available on its own and as part of a deluxe edition of "Born to Die." It presents the same character - a kind of glamorous drifter who may not share a thing with Del Rey's real-life background - but crucially boosts the detail; she sounds invested now in a way she didn't before. And that commitment allows the music to plumb emotional depths even as Del Rey piles on the hand-me-down signifiers suggested by titles like "American," "Cola" and "Body Electric." "I been trying too hard with one pretty song," she moans in "Ride," the lush, Rick Rubin-produced ballad that opens the set. Keep trying, Lana, and you might convince us all.