"Charli has never been shy about collaborating and `Pop 2' is full of co-productions. All but two songs boast a featured artist (and the whole thing was made with PC Music's AG Cook), but there are no gratuitous cameos. Whether it's pop cult queen Carly Rae Jepsen forlornly breaking hearts on the shimmering `Backseat' or Korean-American singer Jay Park on the soft undulation of `Unlock It', everyone not only earns their place, but is heralded by Charli and AG too - the production shifts every time a new guest arrives on the scene, subtly giving them the space to do their own thing. Charli's second mixtape of the year isn't just about proving she's more than your average pop star, but about her settling into her role as innovator, celebrator, and curator supreme".