The answer is RIHANNA, seven letters. Her single Diamonds was released in 2012 as the lead single from the album Unapologetic and went to number one on the Billboard Hot 100. Several other songs called Diamonds exist, so if seven squares is not what you have in front of you, the clue is pointing somewhere else.
The song behind the clue
Diamonds was written by the Australian songwriter Sia and produced by Benny Blanco and StarGate. It is a slower and more open record than most of the Rihanna singles that preceded it, and that contrast accounts for much of why it stood out on release. The singer was born Robyn Rihanna Fenty in Barbados and performs under her middle name alone, and that single name habit is exactly what makes her useful to a constructor.
Seven squares, and the company she keeps there
One name pop stars are a gift to grid builders because they deliver a recognizable full entry without a surname attached. RIHANNA is seven letters. So are BEYONCE, MADONNA and SHAKIRA. That cluster shows up constantly in American grids, and the four of them are close enough in letter pattern that crossings matter more than usual. Check the second letter before committing, because that one square separates RIHANNA from the rest immediately.
The repeated letter is the other thing to watch. RIHANNA carries a double N in the middle, MADONNA carries one late, and BEYONCE and SHAKIRA carry none at all. When a long name slot starts filling in from the middle rather than the ends, a doubled consonant is usually what identifies it before the rest of the letters arrive.

Other Diamonds songs and the names they bring
A clue with the same wording can point at a different record, and the square count is what tells you. Run this list when seven letters is wrong:
| Letters | Answer | The song |
|---|---|---|
| 4 | BAEZ | Diamonds and Rust, Joan Baez, 1975 |
| 5 | SIMON | Diamonds on the Soles of Her Shoes, Paul Simon |
| 6 | MONROE | Diamonds Are a Girl’s Best Friend on film |
| 7 | RIHANNA | Diamonds, 2012 |
| 8 | CHANNING | The same song on Broadway before the film |
Diamonds Are a Girl’s Best Friend is the trap worth knowing properly. Marilyn Monroe sang it in the 1953 film Gentlemen Prefer Blondes, and that is the performance most people picture. The song came from the stage musical first, where Carol Channing introduced it, so a clue about the original run wants a different name than a clue about the movie.
The Neil Diamond misread
Read the clue letter by letter before you answer, because Diamonds singer and Diamond singer are two different questions. The second one could reasonably be asking for NEIL, since Neil Diamond is a singer named Diamond rather than a singer of a song called Diamonds. Constructors are aware of that ambiguity and some of them enjoy it. If you have four squares and the clue has no S on the end, NEIL deserves a look.
The singular causes trouble elsewhere too. Shine On You Crazy Diamond, the Pink Floyd piece, uses it, and so does the Seals and Crofts song Diamond Girl.
How this kind of clue is usually built
Song title clues follow a pattern that is worth internalizing. The title supplies the identification and the answer supplies the person, so the answer is a proper noun and the crossings around it are usually kinder than average. Constructors know that a solver who does not recognize the song is stuck with nothing, so they tend to surround pop culture names with ordinary vocabulary rather than with more names.
That gives you a practical method. If you cannot place the song at all, ignore the clue entirely and solve everything that crosses it. Seven letters filled in from the crossings will usually be enough to recognize a name even if you have never heard the record, and recognizing it beats guessing at it. When a puzzle stacks two unfamiliar proper nouns against each other, that is the point at which most solvers are entitled to feel the grid was unfair rather than that they were underprepared.
Frequently asked questions
Who sang Diamonds and how many letters is the answer?
RIHANNA, seven letters, for the 2012 single from Unapologetic. That is the answer nearly every modern grid wants for this clue.
What if the Diamonds singer clue needs four letters?
Try BAEZ for Diamonds and Rust, or NEIL if the clue actually reads Diamond rather than Diamonds and is pointing at Neil Diamond.
Who wrote Rihanna's Diamonds?
Sia wrote the song, and it was produced by Benny Blanco and StarGate. Grids sometimes clue Sia separately as a three letter entry.