| recordings |
|---|
| 2008-10-28 – 2008-11-02 | Circus | | Britney Spears | 3:35 |
| Circus | | Britney Spears | 3:09 |
| Circus | | Britney Spears | 3:07 |
| Circus | | Britney Spears | 3:39 |
| Circus | | Britney Spears | 3:12 |
| Circus | cover and instrumental | Twinkle Twinkle Little Rock Star | 3:49 |
| Circus | cover | Kidz Bop | 3:03 |
| Circus | cover | Eternal September | 3:54 |
| Circus | cover | MICappella | 2:41 |
| Circus | cover | Dirty Loops | 3:46 |
| Circus (alternative version) | cover | Eternal September | 3:54 |
| Circus (Charlie's lyrics) | | KittenWispy | 3:12 |
| Circus (Diplo Alt Clown mix) | | Britney Spears | 3:12 |
| Circus (Diplo circus remix) | | Britney Spears | 4:25 |
| Circus (Diplo Clown mix) | | Britney Spears | 3:14 |
| Circus (Friscia & Lamboy club mix) | | Britney Spears | 7:52 |
| Circus (Friscia & Lamboy radio remix) | | Britney Spears | 3:49 |
| Circus (Friscia & Lamboy remix) | | Britney Spears | 3:59 |
| Circus (Friscia & Lamboy remix) | | Britney Spears | 5:40 |
| Circus (Joe Bermudez radio remix) | | Britney Spears | 3:41 |
| Circus (Junior Vasquez Club Circus) | | Britney Spears | 9:02 |
| Circus (Junior Vasquez electric circus) | | Britney Spears | 9:02 |
| Circus (Junior Vasquez Ringleader mix) | | Britney Spears | 9:39 |
| Circus (Linus Loves remix) | | Britney Spears | 4:39 |
| Circus (Mysto & Pizzi Electro remix) | | Britney Spears | 4:50 |
| Circus (Tom Neville’s ringleader remix) | | Britney Spears | 7:50 |
| Circus (Tonal remix) | | Britney Spears | 3:38 |
| Circus (Villains remix) | | Britney Spears | 5:17 |
| Circus / Just Dance (2010) | cover and medley | Boyce Avenue | 3:09 |
| Circus / Sweet Dreams (Are Made of This) | medley | Britney Spears / Eurythmics | 2:11 |
| Ghostlight: Cycle Song / Rhythm Song / A True Passion (Genius: Picasso) / Stroke of Genius (Genius: Picasso) / Symphony No. 3 / Ghost Light / Circus | medley | Blue Devils | 11:52 |
