"Who's That Girl" is an up-tempo electro R&B song performed by Australian singer-songwriter Guy Sebastian which features American rapper Eve.

"[14] Sebastian told The New Zealand Herald that it was based on songs he was hearing on the radio from the likes of David Guetta, and The Black Eyed Peas.

[15] Eve said in an interview with Nova FM while she was in Australia to film the video, "I got an email, and when I heard it I was like 'hot song.

It was initially scheduled for radio release four days earlier, but had to be delayed due to last minute tinkering of the song.

[18][19] Sebastian and Eve performed "Who's That Girl" on the grand final episode of The X Factor in November 2010, which aired in both Australia and New Zealand.

[21][22] In the week following The X Factor final Sebastian visited Auckland New Zealand to promote the single and album with an instore appearance and media interviews.

[24] In December 2010 Sebastian performed at a private event to welcome Oprah Winfrey to Sydney during her trip to Australia.

[26] Sebastian sang "Who's That Girl" during Channel Nine's Today at Suncorp Stadium in Brisbane on Australia Day 2011.

[30][31] The Daily Telegraph music editor Kathy McCabe wrote, "This one has one of those choruses which will be on a continuous loop in your head all day.

[....] But this isn't one of those throw away tracks artists stick on a best-of album; not only has it reached the upper echelon of the Australian charts but it has a good shot at breaking him overseas.

"[32] In a review of Twenty Ten Jamie Horne of The Border Mail said, "the dancefloor-ready "Who's That Girl" with US rapper Eve should make it clear that the former 'Fro' is not that uncool after all".

[33] Chris Havercroft from X-Press Magazine wrote, "It is the dancefloor where Sebastian does his most damage and when teaming up with rapper Eve for new single Who's That Girl he shows his knack for targeting his audience".

The simple, uncluttered video shows Sebastian singing about seeing the mystery girl in a dance club, with his mental images of her projected onto the walls.