By mid 1987, Madonna was putting herself about a bit; albums, films, film soundtracks - she was certainly spreading herself very thinly. Fine when there's plenty to go round, but there wasn't. At least not on this single.
Taken from the eponymous movie, 'Who's That Girl' basically presents a re-run of the Latin tinged pop of 'La Isla Bonita' but with all the Spanish musical bells and whistles taken out. Shorn of this baggage, the tune is lighter and given more room to breathe, but there's very little in the way of song wrapped around it and there's only a much repeated chorus refrain of 'Who's That Girl' to put any semblance of meat on the bare bones,
Madonna chooses to sing this in a high and ghostly higher key while the verses themselves are delivered in a sultry low key, both of which are outside of her vocal comfort zone. The effect is to give the track an unfinished feel, as if it's a final demo waiting for the vocalist proper to add her parts. Adding the Spanish phrases 'Quien es esa niña, Señorita mas fina' into the chorus smacks of desperation, an attempt to win over the audience that bought into 'La Isla Bonita' and also to inject a little highbrow sticking plaster onto a lowbrow sucking chest wound, but it's effective as wrapping greasy chips in a copy of The Times and trying to pass them off as caviar.
'Who's That Girl' is presented without a question mark, maybe because the question here isn't so much 'Who's That Girl?' but 'Where's The Song?' We all know who the girl is, it's Madonna, and had it been anyone else at the helm then this thinly sliced piece of inconsequential confection would have struggled to make the top fifty, let alone number one.