Rating: 3/5

Verdict: Overly long, yet saucy return from hot sexy momma.

How do you craft a chart-topping pop album these days? The short, and easiest answer is, don't bother. Arguably, unless you're pint-sized teen sensation Justin Bieber it seems, pop is best when it comes in short sharp shocks. For example, Lady Gaga's mega-selling debut of a few years ago had its shonky tracks, and it was far better suited to radio singles and pick and mix downloads than a long player; and Christina Aguilera has a similar problem on her fourth album, Bionic.

Along with Britney, Beyonce, and Madonna, Aguilera was one of the top pop chicks of the late 90s and 2000s - and this is her return after four years during which time she toured solidly and had a baby.

As well as being a mum to wee two-year-old Max she's managed to record this - overly long - 15-track album and by the sounds of one song, she still gets time to have "sex before breakfast". Ah the joys of being able to afford a fleet of nannies.

The album vamps it up and struts along quite nicely for the first three tracks, including 80s synth-driven single Not Myself Tonight. (She got bagged for copying Gaga in the video for that song, which is unfair considering Aguilera started wearing next to nothing and humping the floor way back in 2002 - well before Gaga donned her oil rig-like platform shoes and strode into the spotlight.)

Another early highlight of the album is the sonic whoop and rap of Woohoo, with its Beyonce-meets-M.I.A. style, but then comes Elastic Love (co-written by M.I.A.) which sounds a little contrived because of its hopelessly literal lyrics; and the empty banging beats and fake brassy pizzazz of Desnudate is grating.

Following the first of three short spoken-word intros, she's back on track with the whispy Vogue-like electro tech house of Glam and the frenetic and inventive Prima Donna, before settling into a string of swooning pop serenades. Aguilera does these well because she's still got some of the best pipes in pop music. However, songs like Sex For Breakfast sound sweet, and almost clinical, when you want sexy and sordid, and Lift Me Up is soppy, instead of stirring.

Being a mum plays a big part on songs such as All I Need and I Am, where she's almost wistful and folky - and who can blame her for singing about her little one? But these slower songs make the album a long and drawn-out listen. Before the end she shakes things up again with the shouty pop of I Hate Boys, and the electro groove of My Girls with Peaches.

The album booklet beats the leather pants off Gaga too - so be warned, don't spend too long reading the lyrics because the accompanying photos might make it a little embarrassing, if someone catches you.