Circus font here refers to the font used in the album cover of Circus, which is the sixth studio album by the American singer Britney Spears released in 2008.
The lettering for the singer name set in a wavy style is very similar to a font named Matamoros NF designed by Nick’s Fonts while the album title font resembles Number 514 designed by Jordan Davies. Both are commercial fonts and you can view more details about them here and here respectively.
Download Circus Font
We are currently unable to find a free alternative or a font similar to the commercial font identified above, and you will need to follow the relevant links above and purchase the font.