Following his 2006 sophomore album, Friendly Fire, Sean Lennon struck up a romance with model Charlotte Kemp Muhl, their relationship soon turning musical as they formed the duo the Ghost of a Saber Tooth Tiger.

The first fruit of their labor is Acoustic Sessions, a spacy baroque-folk fantasia floating on overdubbed harmonies and gently plucked guitars, accentuated by harmoniums and keyboards that sound like old music boxes.

It's a delicate, precious setting, not overly fussy but certainly mannered in its bohemian allusions, whether deliberate Abbey Road references or Lennon and Muhl singing about Aristotle and "Shroedinger’s Cat." Everything here is so gentle it threatens to drift away, but its muted nature is a nice contrast to Lennon's previous records, which tended to be overthought and undercooked.

Acoustic Sessions has more in common with his off-kilter soundtrack to Rosencrantz and Guildenstern Are Undead -- it's not studied, it's casual, which means that even if it's not devoid of whimsy it's not self-satisfied about it, and that's a welcome change.