diff --git a/modules/juce_audio_basics/midi/juce_MidiMessage.cpp b/modules/juce_audio_basics/midi/juce_MidiMessage.cpp
index c0261ab768..a334dfe89e 100644
--- a/modules/juce_audio_basics/midi/juce_MidiMessage.cpp
+++ b/modules/juce_audio_basics/midi/juce_MidiMessage.cpp
@@ -841,7 +841,7 @@ bool MidiMessage::isKeySignatureMetaEvent() const noexcept
 
 int MidiMessage::getKeySignatureNumberOfSharpsOrFlats() const noexcept
 {
-    return (int) getMetaEventData()[0];
+    return (int) (int8) getMetaEventData()[0];
 }
 
 bool MidiMessage::isKeySignatureMajorKey() const noexcept