diff --git a/modules/libpref/public/Preferences.h b/modules/libpref/public/Preferences.h
index 751e8b231267..a95d233565e2 100644
--- a/modules/libpref/public/Preferences.h
+++ b/modules/libpref/public/Preferences.h
@@ -201,6 +201,7 @@ public:
   {
     return SetInt(aPref, static_cast<int32_t>(aValue));
   }
+  static nsresult SetFloat(const char* aPref, float aValue);
   static nsresult SetCString(const char* aPref, const char* aValue);
   static nsresult SetCString(const char* aPref, const nsACString &aValue);
   static nsresult SetString(const char* aPref, const char16_t* aValue);
@@ -349,7 +350,6 @@ public:
   static void SetPreference(const PrefSetting& aPref);
 
   static int64_t SizeOfIncludingThisAndOtherStuff(mozilla::MallocSizeOf aMallocSizeOf);
-  static nsresult SetFloat(const char* aPref, float aValue);
 
 protected:
   virtual ~Preferences();
diff --git a/modules/libpref/src/Preferences.cpp b/modules/libpref/src/Preferences.cpp
index 8fae914f680e..3541f70f633e 100644
--- a/modules/libpref/src/Preferences.cpp
+++ b/modules/libpref/src/Preferences.cpp
@@ -1567,6 +1567,13 @@ Preferences::SetInt(const char* aPref, int32_t aValue)
   return PREF_SetIntPref(aPref, aValue, false);
 }
 
+// static
+nsresult
+Preferences::SetFloat(const char* aPref, float aValue)
+{
+  return SetCString(aPref, nsPrintfCString("%f", aValue).get());
+}
+
 // static
 nsresult
 Preferences::SetComplex(const char* aPref, const nsIID &aType,