diff --git a/test/Altinn.App.Api.Tests/Controllers/InstancesController_PostNewInstance.cs b/test/Altinn.App.Api.Tests/Controllers/InstancesController_PostNewInstance.cs
index c4a32508f..9f35a49de 100644
--- a/test/Altinn.App.Api.Tests/Controllers/InstancesController_PostNewInstance.cs
+++ b/test/Altinn.App.Api.Tests/Controllers/InstancesController_PostNewInstance.cs
@@ -87,15 +87,18 @@ private async Task<Instance> CreateInstanceSimplified(
         string app,
         int instanceOwnerPartyId,
         HttpClient client,
-        string token
+        string token,
+        Dictionary<string, string>? prefill = null
     )
     {
         client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
 
+        prefill ??= new();
+
         // Create instance data
         var body = $$"""
                 {
-                    "prefill": {},
+                    "prefill": {{JsonSerializer.Serialize(prefill)}},
                     "instanceOwner": {
                         "partyId": "{{instanceOwnerPartyId}}"
                     }
@@ -139,6 +142,38 @@ public async Task PostNewInstance_Simplified()
         readDataElementResponseParsed.Melding.Should().BeNull(); // No content yet
     }
 
+    [Fact]
+    public async Task PostNewInstance_Simplified_With_Prefill()
+    {
+        // Setup test data
+        string org = "tdd";
+        string app = "contributer-restriction";
+        int instanceOwnerPartyId = 501337;
+        HttpClient client = GetRootedClient(org, app);
+        string token = PrincipalUtil.GetToken(1337, null);
+
+        var prefill = new Dictionary<string, string> { { "melding.name", "TestName" }, };
+        var createResponseParsed = await CreateInstanceSimplified(
+            org,
+            app,
+            instanceOwnerPartyId,
+            client,
+            token,
+            prefill
+        );
+        var instanceId = createResponseParsed.Id;
+        createResponseParsed.Data.Should().HaveCount(1, "Create instance should create a data element");
+        var dataGuid = createResponseParsed.Data.First().Id;
+
+        // Verify stored data
+        var readDataElementResponse = await client.GetAsync($"/{org}/{app}/instances/{instanceId}/data/{dataGuid}");
+        readDataElementResponse.StatusCode.Should().Be(HttpStatusCode.OK);
+        var readDataElementResponseContent = await readDataElementResponse.Content.ReadAsStringAsync();
+        var readDataElementResponseParsed = JsonSerializer.Deserialize<Skjema>(readDataElementResponseContent)!;
+        Assert.NotNull(readDataElementResponseParsed.Melding);
+        readDataElementResponseParsed.Melding.Name.Should().Be("TestName");
+    }
+
     [Fact]
     public async Task PostNewInstanceWithInvalidData_EnsureInvalidResponse()
     {