I'm relatively new to music theory. I'm really racking my brain trying to justify this Chord progression from Sam Smiths "I'm not the only one"

It goes F major to A7 to D minor.

I'm confused because how does A7 fit into F major? It has to have something to do with modal interchange, but I just can't figure out what. How can you just borrow that c#?

Anyway I came to this forum because I'm at a loss... Can anyone explain it?

Thanks in advance! :)


3 Answers 3


A7 doesn't fit in F major. It, however, fits in D minor.

The A7 in the context of F major is a secondary dominant - a borrowed dominant of a non-tonic chord in that key. Roman numeral-wise, this A7 to D minor is V7/vi to vi.

  • Oh I see so since C sharp is a leading tone in D melodic minor you can use it to lead to D minor in the key of F major? Jul 6, 2018 at 7:05
  • 1
    Yes, you can "pretend" any chord in a key is the tonic of its own key, and precede it with its own dominant (or dominant 7th) chord. Those chords are called "secondary dominants". They often contain notes not in the scale of the original key. So chord progressions like F A7 Dm, or F G7 (with B natural) C, sound OK. In fact you can have two (or even more) secondary dominants in sequence, for example F E7 A7 Dm, Where the E7 is the secondary dominant of A7. Try it yourself! The E7 chord has two notes not in the original scale of F (G# and B natural) but all these chords are still in key F.
    – user19146
    Jul 6, 2018 at 9:49
  • 1
    @alephzero - saying all these chords are in key F is taking it too far - and it's not true! Could be said that all the chords can be found in a piece which is in the key of F, but that's true, and not the same.
    – Tim
    Jul 6, 2018 at 17:49
  • In this example, the chords are all IN key F because (if I remember the song correctly) there's no modulation. It's III7 - VI in F major, not V7 - I in D minor. Yes, I'm being pedantic. But it's just as pedantic to get stuck in diatonicism.
    – Laurence
    Jul 7, 2018 at 10:42
  • @Laurence Payne - There's also such a thing as tonicization, which covers these very fleeting "modulations". While I agree that this piece probably never modulates into another key, this piece tonicizes that D minor chord, IMO. It's just like "The Star-Spangled Banner" - never honestly leaves its home key, still pointedly uses a secondary dominant and tonicizes the dominant (unless you want to use an even stranger harmonization at that point).
    – Dekkadeci
    Jul 7, 2018 at 17:16

The A7 fits in D minor, the relative major key to F major. The chord can be found in the D harmonic or melodic minor. It's placed there to create a resolution to D minor which is being considered as the I (One), the starting and ending place for the melody. The fact that it started on F maj then moved to D min with such a chord hints at a modulation from F maj to D min. Though I'd refrain from committing to that w/o hearing the melody.

  • If I remember right the song goes F A7 Dm Bb in a loop. It's not a modulation.
    – coconochao
    Jul 6, 2018 at 14:48
  • I didn't see any mention of the Bd, but that still fits. I --> iii(dom7) --> vi --> IV. It is not uncommon to treat a passing chord as a temporary I and put its V7 before it (at least in Jazz).
    – user50691
    Jul 6, 2018 at 15:43
  • Yes, I was just providing you with more information about the song since you mentioned a possible modulation.
    – coconochao
    Jul 6, 2018 at 15:46
  • That helps.....
    – user50691
    Jul 6, 2018 at 15:48

Someone, somewhere, seems to be giving many, many players an idea that every tune must only contain diatonic notes. It's just not true!

A lot of tunes only contain diatonic notes, but, there are probably more out there which will have notes that do not belong to a particular key.

To an extent they're the ones that find their way into melodies and harmonies, that make songs more interesting. It's often the unexpected that does it.

Nothing has to be borrowed from anywhere else, although often these occurrences can be explained away with some theory.

As Dekkadeci states, it's the dominant chord of the relative minor chord of the key. Known as V7/vi. Now, with a little theory, one thinks 'ah, but the relative natural minor of F is Dm. Dm only has Bb as an 'altered' note.'

But, there are other changed notes in other minors, and looking at both the melodic and harmonic minor scales, it's apparent that C# lives in them. So, theory says it's o.k. to use C# whilst in key F. And the reason is that C# is the leading note of Dm, making the C#>D change much more convincing than C>D.

In fact, theory says any of the 12 notes can be used in any of the 12 keys. What it does not say is that pieces should be restricted to only diatonic notes. There are many questions very similar to this, and really, there's no need for them!

  • Oh I see so since C sharp is a leading tone in melodic minor you can use it to lead to D minor in the key of F? Jul 6, 2018 at 7:02
  • Yes. But no-one is making rules that anyone has to follow. It sounds good, therefore it is good. And then, someone had the idea of including the concept in what we call 'theory'.
    – Tim
    Jul 6, 2018 at 7:09
  • Oh Ok! Thanks so much! Sorry I'm kinda new to this whole thing. Jul 6, 2018 at 9:01
  • That's fine. Now is the perfect time to realise that music theory is just that. Theory. Not law!
    – Tim
    Jul 6, 2018 at 9:03
  • At last! I have a disciple. :-)
    – Laurence
    Jul 6, 2018 at 17:27

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