In her new album “It’s Not Me It’s You,” notorious British bad girl Lily Allen addresses more mature issues, but stays true to her infamous sincerity, blunt truthfulness, and in-your-face lyrics.

Her debut, “Alright, Still,” spread Allen’s reputation as an outspoken pop singer with upbeat and poppy songs in which she complained about men, bureaucrats, paparazzi, and all other grievances.

Allen has become a star in Britain not only because of her music, but also by her reputation for late-night stumbles out of bars, bad language and rebellious behavior towards the press, and drug and alcohol abuse which she battled via her MySpace blog. “It’s Not Me, It’s You” marks Allen’s development as an artist as she tackles everything: drugs, sex, religion, and materialism.

Her single, “The Fear,” which criticizes the materialism and fame of the music industry, shows listeners that this new album does not focus on high-spirited tunes of her previous songs.

But have no fear, her album retains the original wittiness and spunk that made Allen stand out in the first place. In “Guess Who Batman,” (which appears in the album under a more explicit name) Allen asks, “Do you really enjoy/living a life that’s so hateful?/’Cause there’s a hole where your soul should be./You’re losing control of it/and it’s really distasteful.”

“It’s Not Me, It’s You” not only moves away from her previous album with heavier topics, but also with a new tone. Her first album was primarily composed of lively and frolicsome tunes, while this album features more complex and deeper melodies that are still as captivating.

“Back to the Start” features an especially catchy and fast tune that incorporates electronic sounds and various effects that make it nearly impossible to not follow along.

While Allen clearly excites people with her upbeat songs and gutsy attitude, her spunky British accent, which infiltrates her singing to produce a signature sound, separates her from other female pop singers.

Allen has taken her old, witty and sharp-tongued attitude and applied it to new, heavier themes in her second album. However, she still manages to incorporate her signature sophomoric and entertaining rants about desperate suitors, body image, and the shortcomings of boyfriends, which make Allen’s “It’s Not Me, It’s You” a true masterpiece of lighthearted British pop.