diff --git a/src/pbrt/util/spectrum.h b/src/pbrt/util/spectrum.h
index 8b2ae4810..943a9993c 100644
--- a/src/pbrt/util/spectrum.h
+++ b/src/pbrt/util/spectrum.h
@@ -85,7 +85,6 @@ DenselySampledSpectrum D(Float T, Allocator alloc);
 
 Float SpectrumToPhotometric(Spectrum s);
 
-Float SpectrumToPhotometric(Spectrum s);
 XYZ SpectrumToXYZ(Spectrum s);
 
 // SampledSpectrum Definition