diff --git a/plugins/fetchinvoice.c b/plugins/fetchinvoice.c
index 8882a8f0a..6d1b01067 100644
--- a/plugins/fetchinvoice.c
+++ b/plugins/fetchinvoice.c
@@ -253,8 +253,11 @@ static struct command_result *handle_invreq_response(struct command *cmd,
 	if ((badfield = field_diff(sent->invreq, inv, payer_info)))
 		goto badinv;
 
-	/* Get the amount we expected. */
-	if (sent->offer->amount && !sent->offer->currency) {
+	/* Get the amount we expected: firstly, if that's what we sent,
+	 * secondly, if specified in the invoice. */
+	if (sent->invreq->amount) {
+		expected_amount = tal_dup(tmpctx, u64, sent->invreq->amount);
+	} else if (sent->offer->amount && !sent->offer->currency) {
 		expected_amount = tal(tmpctx, u64);
 
 		*expected_amount = *sent->offer->amount;
diff --git a/tests/test_pay.py b/tests/test_pay.py
index 8e870723b..433e35e1b 100644
--- a/tests/test_pay.py
+++ b/tests/test_pay.py
@@ -4158,6 +4158,15 @@ def test_fetchinvoice(node_factory, bitcoind):
     with pytest.raises(RpcError, match="Remote node sent failure message.*Amount must be at least 2msat"):
         l1.rpc.call('fetchinvoice', {'offer': offer1['bolt12'], 'msatoshi': 1})
 
+    # If no amount is specified in offer, one must be in invoice.
+    offer_noamount = l3.rpc.call('offer', {'amount': 'any',
+                                           'description': 'any amount test'})
+    with pytest.raises(RpcError, match="msatoshi parameter required"):
+        l1.rpc.call('fetchinvoice', {'offer': offer_noamount['bolt12']})
+    inv1 = l1.rpc.call('fetchinvoice', {'offer': offer_noamount['bolt12'], 'msatoshi': 100})
+    # But amount won't appear in changes
+    assert 'msat' not in inv1['changes']
+
     # Single-use invoice can be fetched multiple times, only paid once.
     offer2 = l3.rpc.call('offer', {'amount': '1msat',
                                    'description': 'single-use test',