diff --git a/Tests/test_image_convert.py b/Tests/test_image_convert.py
index a4c5490102f..7a8a9e78c89 100644
--- a/Tests/test_image_convert.py
+++ b/Tests/test_image_convert.py
@@ -317,6 +317,20 @@ def test_p2pa_palette() -> None:
     assert im_pa.getpalette(None) == im.getpalette()
 
 
+@pytest.mark.parametrize(
+    "mode, value",
+    (("1", 255), ("L", 128), ("RGB", (1, 2, 3)), ("I;16", 0x1234), ("I", 0x12345)),
+)
+def test_trns_to_pa(mode: str, value: int | tuple[int, int, int]) -> None:
+    im = Image.new(mode, (2, 1))
+    im.putpixel((1, 0), value)
+    im.info["transparency"] = value
+
+    im_pa = im.convert("PA")
+    assert "transparency" not in im_pa.info
+    assert im_pa.getchannel("A").get_flattened_data() == (255, 0)
+
+
 rgb2xyz_matrix = (
     0.412453, 0.357580, 0.180423, 0,
     0.212671, 0.715160, 0.072169, 0,
diff --git a/src/PIL/Image.py b/src/PIL/Image.py
index c76bebcfb94..8c837a5f661 100644
--- a/src/PIL/Image.py
+++ b/src/PIL/Image.py
@@ -1198,6 +1198,12 @@ def convert_transparency(
                 else:
                     msg = "Transparency for P mode should be bytes or int"
                     raise ValueError(msg)
+            elif self.mode in {"1", "L", "I", "I;16", "RGB"} and mode == "PA":
+                im_without_trns = self.copy()
+                del im_without_trns.info["transparency"]
+                new_im = im_without_trns.convert(mode, dither=dither)
+                new_im.putalpha(self.convert("RGBA").getchannel("A"))
+                return new_im
 
         if mode == "P" and palette == Palette.ADAPTIVE:
             im = self.im.quantize(colors)