diff --git a/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py b/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py
index aaf357effa6..0e5b2952377 100644
--- a/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py
+++ b/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py
@@ -580,6 +580,8 @@ class AmazonAnthropicClaudeMessagesConfig(
                 content = msg.get("content")
                 if isinstance(content, str):
                     if content:
+                        if content.startswith("x-anthropic-billing-header:"):
+                            continue
                         block = {"type": "text", "text": content}
                         if "cache_control" in msg:
                             block["cache_control"] = msg["cache_control"]
@@ -590,6 +592,10 @@ class AmazonAnthropicClaudeMessagesConfig(
                             if item.get("type") == "text":
                                 text_val = item.get("text")
                                 if text_val:
+                                    if text_val.startswith(
+                                        "x-anthropic-billing-header:"
+                                    ):
+                                        continue
                                     block = {"type": "text", "text": text_val}
                                     if "cache_control" in item:
                                         block["cache_control"] = item["cache_control"]
diff --git a/tests/test_litellm/llms/bedrock/messages/invoke_transformations/test_anthropic_claude3_transformation.py b/tests/test_litellm/llms/bedrock/messages/invoke_transformations/test_anthropic_claude3_transformation.py
index 6bfd656568a..2840bf27b3f 100644
--- a/tests/test_litellm/llms/bedrock/messages/invoke_transformations/test_anthropic_claude3_transformation.py
+++ b/tests/test_litellm/llms/bedrock/messages/invoke_transformations/test_anthropic_claude3_transformation.py
@@ -1868,3 +1868,40 @@ def test_bedrock_anthropic_messages_system_role_transformation():
         {"content": "no_role_key"},
         {"role": "user", "content": "Hello"},
     ]
+
+    # 11. Test case: system message in messages array containing billing-header as string (should be skipped)
+    req = config.transform_anthropic_messages_request(
+        model="bedrock/us.anthropic.claude-sonnet-4-5-20250929-v1:0",
+        messages=[
+            {"role": "system", "content": "x-anthropic-billing-header:some-billing-id"},
+            {"role": "user", "content": "Hello"},
+        ],
+        anthropic_messages_optional_request_params={"max_tokens": 100},
+        litellm_params={},
+        headers={},
+    )
+    assert req["messages"] == [{"role": "user", "content": "Hello"}]
+    assert "system" not in req
+
+    # 12. Test case: system message in messages array containing billing-header inside list (should be skipped)
+    req = config.transform_anthropic_messages_request(
+        model="bedrock/us.anthropic.claude-sonnet-4-5-20250929-v1:0",
+        messages=[
+            {
+                "role": "system",
+                "content": [
+                    {
+                        "type": "text",
+                        "text": "x-anthropic-billing-header:some-billing-id",
+                    },
+                    {"type": "text", "text": "Valid system prompt"},
+                ],
+            },
+            {"role": "user", "content": "Hello"},
+        ],
+        anthropic_messages_optional_request_params={"max_tokens": 100},
+        litellm_params={},
+        headers={},
+    )
+    assert req["messages"] == [{"role": "user", "content": "Hello"}]
+    assert req["system"] == [{"type": "text", "text": "Valid system prompt"}]