diff --git a/app/src/main/java/com/keylesspalace/tusky/entity/Attachment.kt b/app/src/main/java/com/keylesspalace/tusky/entity/Attachment.kt
index 3517ff09..1de7bd78 100644
--- a/app/src/main/java/com/keylesspalace/tusky/entity/Attachment.kt
+++ b/app/src/main/java/com/keylesspalace/tusky/entity/Attachment.kt
@@ -28,7 +28,7 @@ import kotlinx.android.parcel.Parcelize
 data class Attachment(
         val id: String,
         val url: String,
-        @SerializedName("preview_url") val previewUrl: String,
+        @SerializedName("preview_url") val previewUrl: String?, // can be null for e.g. audio attachments
         val meta: MetaData?,
         val type: Type,
         val description: String?,