diff --git a/homeassistant/components/todoist/calendar.py b/homeassistant/components/todoist/calendar.py
index 02459b429c4..645fea865ea 100644
--- a/homeassistant/components/todoist/calendar.py
+++ b/homeassistant/components/todoist/calendar.py
@@ -1,9 +1,7 @@
 """Support for Todoist task management (https://todoist.com)."""
 from __future__ import annotations
 
-import asyncio
 from datetime import date, datetime, timedelta
-from itertools import chain
 import logging
 from typing import Any
 import uuid
@@ -117,8 +115,6 @@ async def async_setup_platform(
 
     # Look up IDs based on (lowercase) names.
     project_id_lookup = {}
-    label_id_lookup = {}
-    collaborator_id_lookup = {}
 
     api = TodoistAPIAsync(token)
 
@@ -126,9 +122,6 @@ async def async_setup_platform(
     # Grab all projects.
     projects = await api.get_projects()
 
-    collaborator_tasks = (api.get_collaborators(project.id) for project in projects)
-    collaborators = list(chain.from_iterable(await asyncio.gather(*collaborator_tasks)))
-
     # Grab all labels
     labels = await api.get_labels()
 
@@ -142,13 +135,6 @@ async def async_setup_platform(
         # Cache the names so we can easily look up name->ID.
         project_id_lookup[project.name.lower()] = project.id
 
-    # Cache all label names
-    label_id_lookup = {label.name.lower(): label.id for label in labels}
-
-    collaborator_id_lookup = {
-        collab.name.lower(): collab.id for collab in collaborators
-    }
-
     # Check config for more projects.
     extra_projects: list[CustomProject] = config[CONF_EXTRA_PROJECTS]
     for extra_project in extra_projects:
@@ -194,14 +180,16 @@ async def async_setup_platform(
         data: dict[str, Any] = {"project_id": project_id}
 
         if task_labels := call.data.get(LABELS):
-            data["label_ids"] = [
-                label_id_lookup[label.lower()] for label in task_labels
-            ]
+            data["labels"] = task_labels
 
         if ASSIGNEE in call.data:
+            collaborators = await api.get_collaborators(project_id)
+            collaborator_id_lookup = {
+                collab.name.lower(): collab.id for collab in collaborators
+            }
             task_assignee = call.data[ASSIGNEE].lower()
             if task_assignee in collaborator_id_lookup:
-                data["assignee"] = collaborator_id_lookup[task_assignee]
+                data["assignee_id"] = collaborator_id_lookup[task_assignee]
             else:
                 raise ValueError(
                     f"User is not part of the shared project. user: {task_assignee}"
diff --git a/tests/components/todoist/test_calendar.py b/tests/components/todoist/test_calendar.py
index adf0f8a14b0..9c0680d1443 100644
--- a/tests/components/todoist/test_calendar.py
+++ b/tests/components/todoist/test_calendar.py
@@ -1,14 +1,21 @@
 """Unit tests for the Todoist calendar platform."""
-from datetime import datetime, timedelta
+from datetime import timedelta
 from http import HTTPStatus
 from unittest.mock import AsyncMock, patch
 import urllib
 
 import pytest
-from todoist_api_python.models import Due, Label, Project, Task
+from todoist_api_python.models import Collaborator, Due, Label, Project, Task
 
 from homeassistant import setup
-from homeassistant.components.todoist.calendar import DOMAIN
+from homeassistant.components.todoist.const import (
+    ASSIGNEE,
+    CONTENT,
+    DOMAIN,
+    LABELS,
+    PROJECT_NAME,
+    SERVICE_NEW_TASK,
+)
 from homeassistant.const import CONF_TOKEN
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers import entity_registry as er
@@ -30,9 +37,7 @@ def mock_task() -> Task:
         created_at="2021-10-01T00:00:00",
         creator_id="1",
         description="A task",
-        due=Due(
-            is_recurring=False, date=datetime.now().strftime("%Y-%m-%d"), string="today"
-        ),
+        due=Due(is_recurring=False, date=dt.now().strftime("%Y-%m-%d"), string="today"),
         id="1",
         labels=["Label1"],
         order=1,
@@ -68,7 +73,9 @@ def mock_api(task) -> AsyncMock:
     api.get_labels.return_value = [
         Label(id="1", name="Label1", color="1", order=1, is_favorite=False)
     ]
-    api.get_collaborators.return_value = []
+    api.get_collaborators.return_value = [
+        Collaborator(email="user@gmail.com", id="1", name="user")
+    ]
     api.get_tasks.return_value = [task]
     return api
 
@@ -193,3 +200,31 @@ async def test_all_day_event(
         }
     ]
     assert events == expected
+
+
+@patch("homeassistant.components.todoist.calendar.TodoistAPIAsync")
+async def test_create_task_service_call(todoist_api, hass: HomeAssistant, api) -> None:
+    """Test api is called correctly after a new task service call."""
+    todoist_api.return_value = api
+    assert await setup.async_setup_component(
+        hass,
+        "calendar",
+        {
+            "calendar": {
+                "platform": DOMAIN,
+                CONF_TOKEN: "token",
+            }
+        },
+    )
+    await hass.async_block_till_done()
+
+    await hass.services.async_call(
+        DOMAIN,
+        SERVICE_NEW_TASK,
+        {ASSIGNEE: "user", CONTENT: "task", LABELS: ["Label1"], PROJECT_NAME: "Name"},
+    )
+    await hass.async_block_till_done()
+
+    api.add_task.assert_called_with(
+        "task", project_id="12345", labels=["Label1"], assignee_id="1"
+    )