diff --git a/source/core/actorlist.cpp b/source/core/actorlist.cpp
index a7591027d..4b3be68d5 100644
--- a/source/core/actorlist.cpp
+++ b/source/core/actorlist.cpp
@@ -509,6 +509,7 @@ DEFINE_FIELD_NAMED(DCoreActor, sprext.roll, roll)
 DEFINE_FIELD_NAMED(DCoreActor, sprext.renderflags, renderflags)
 DEFINE_FIELD_NAMED(DCoreActor, sprext.alpha, alpha)
 DEFINE_FIELD_NAMED(DCoreActor, time, spawnindex)
+DEFINE_FIELD_NAMED(DCoreActor, spritesetindex, spritesetpic)
 
 DEFINE_ACTION_FUNCTION(DCoreActor, pos)
 {
@@ -585,7 +586,11 @@ DEFINE_ACTION_FUNCTION_NATIVE(DCoreActor, addz, coreactor_addz)
 void coreactor_setSpritePic(DCoreActor* self, unsigned z)
 {
 	auto &spriteset = static_cast<PClassActor*>(self->GetClass())->ActorInfo()->SpriteSet;
-	if (z < spriteset.Size()) self->spr.picnum = spriteset[z];
+	if (z < spriteset.Size())
+	{
+		self->spritesetindex = z;
+		self->spr.picnum = spriteset[z];
+	}
 }
 
 DEFINE_ACTION_FUNCTION_NATIVE(DCoreActor, setSpritePic, coreactor_setSpritePic)
diff --git a/source/core/coreactor.h b/source/core/coreactor.h
index c8fc9af87..ed89e71e1 100644
--- a/source/core/coreactor.h
+++ b/source/core/coreactor.h
@@ -30,6 +30,8 @@ public:
 	vec3_t opos;
 	int time;
 	int16_t oang;
+	int16_t spritesetindex;
+
 
 	DCoreActor() = default;
 	virtual ~DCoreActor() = default;
diff --git a/source/core/savegamehelp.cpp b/source/core/savegamehelp.cpp
index eaa57d653..300a93815 100644
--- a/source/core/savegamehelp.cpp
+++ b/source/core/savegamehelp.cpp
@@ -674,6 +674,7 @@ void DCoreActor::Serialize(FSerializer& arc)
 		("nextsect", nextSect)
 		("sprite", spr)
 		("time", time)
+		("spritesetindex", spritesetindex)
 		("spriteext", sprext);
 
 	if (arc.isReading()) spsmooth = {};
diff --git a/source/games/duke/src/savegame.cpp b/source/games/duke/src/savegame.cpp
index 9bf7562dd..17e84c8ac 100644
--- a/source/games/duke/src/savegame.cpp
+++ b/source/games/duke/src/savegame.cpp
@@ -306,7 +306,6 @@ void DDukeActor::Serialize(FSerializer& arc)
 		("actorstayput", actorstayput)
 		("dispicnum", dispicnum)
 		("basepicnum", basepicnum)
-		("spritesetindex", spritesetindex)
 		("timetosleep", timetosleep)
 		("floorz", floorz)
 		("ceilingz", ceilingz)
diff --git a/source/games/duke/src/types.h b/source/games/duke/src/types.h
index 27e75a09c..7ae1be049 100644
--- a/source/games/duke/src/types.h
+++ b/source/games/duke/src/types.h
@@ -47,7 +47,7 @@ public:
 	uint8_t cgg;
 	uint8_t spriteextra;	// moved here for easier maintenance. This was originally a hacked in field in the sprite structure called 'filler'.
 	short attackertype, hitang, hitextra, movflag;
-	short tempang, dispicnum, basepicnum, spritesetindex;
+	short tempang, dispicnum, basepicnum;
 	short timetosleep;
 	vec2_t ovel;
 	int floorz, ceilingz;
diff --git a/wadsrc/static/zscript/coreactor.zs b/wadsrc/static/zscript/coreactor.zs
index 4a80c7a8f..49b84354e 100644
--- a/wadsrc/static/zscript/coreactor.zs
+++ b/wadsrc/static/zscript/coreactor.zs
@@ -4,7 +4,7 @@ class CoreActor native
 	//native readonly sectortype sectp;
 
 	native int16 cstat;
-	native int16 picnum;
+	//native int16 picnum; // access is disabled to allow later refactoring.
 	native readonly int16 statnum;
 	native int16 ang;
 	native int16 xvel;
@@ -33,6 +33,7 @@ class CoreActor native
 	native uint8 renderflags;
 	native float alpha;
 
+	native readonly int16 spritesetpic;
 	native readonly int spawnindex;
 
 	// note that the pos vector is not directly accessible here.