The synth-pop track samples the composition of "Ain't No Mountain High Enough" by Diana Ross.

It follows a chord progression of G–A–F♯m–Bm, and the song is set in common time with a tempo of 124 beats per minute.

The icing on the cake is a line borrowed from the Diana Ross version of 'Ain't No Mountain High Enough'.

[12] Teen People called the song a fun, frothy dance track reminiscent of early Madonna.

Music download of the song gained media attention because it was made available in MP3 format, without digital rights management, which is normally used to restrict copying of commercially released singles.

The increased price was rationalized not by the DRM-free format, but by offering users the ability to "personalize" the song with a specific name.

In the United States, the single debuted at number 39 on the Billboard Hot 100, on the issue dated July 15, 2006.

[17][18] On August 12, 2006, the single peaked at number 14 and was awarded the honor of that week's Greatest Gainer Digital.

On Hot Dance Club Play chart, the single peaked at number one on the issues dated October 7, 2006.

[25] In Canada, "A Public Affair" became Simpson's third top ten single after "Take My Breath Away" (2004), peaking at number eight in July 2006.

It introduces Australian Reshad Strik, whose participation precipitated many comments on his resemblance to Nick Lachey, Simpson's ex-husband, and Menounos, who resembled Vanessa Minnillo, who was dating Lachey at the time Simpson split with her ex-husband.

[33] According with MTV, the music video was heavily influenced by Olivia Newton-John's "Xanadu" and some Madonna's videos like "Sorry" and "Music" taking references to choreographed roller-skating and celeb making a cameo as the star's chauffeur, respectively.

[34] On July 19, Simpson visited MTV's Total Request Live to premiere the video.