Hi! Ummmm.....the font used in this photo looks like it would be closely related to the Basics>Sans Serif font family.
The following fonts look similar to the font used Adele's 21 album cover:
Existence Light
Europe Underground
Hope that this helped!

NOT positive, but i've been wondering the same thing. Helvetica Neue LT Std has a bunch of options that match it. I like 45 light.
ROR
Try Avant Garde Xtralight. Very similar.
font for "21"
(lol. Typo in the font name. "Typograph"
)
Editado el 16/12/2011 a las 19:11 por styrofoamballs
none of these are the same font used for ADELE. I can't find it anywhere.
Since the grave has been opened, as close as I get. Close but no perfect match (A, E, 2).
Someone made a typeface out of this a few weeks ago.
Closer. Still not a perfect match.
The font is Sevigne Regular.
The exact font that is used here is called Rosemary Samuels Thin.
MMaaikeM ha dicho 
The exact font that is used here is called Rosemary Samuels Thin.
Rosemary Samuels Thin
My preview must be different than yours, because mine isn't identical
Anyway, I can't remember other request with 9 suggestions for only one font

Try Century Gothic on Microsoft PowerPoint or Microsoft Paint. I tried it on Microsoft PowerPoint with 21 and it looked similar.
With custom E
Fuente sugerida: Neutra Display Thin Alternate
Editado el 21/04/2013 a las 18:36 por Carl.2
Fuente sugerida: Adele
(Ya se ha sugerido aquí)
Editado el 29/01/2014 a las 22:12 por claudeserieux
Huso horario CEST. Ahora son las 21:17