TempData persistence

I've been working with TempData lately and facing a confusing case:

Supposing that the TempData is created in the following Action:

public ActionResult MyAction1()
{
  //...
  myTempData = TempData["myTempData"];
  //..
}

and is expected to be use in the following Action:

public ActionResult MyAction2()
{
  //...
  TempData["myTempData"] = myTempData;
  //..
}

I understand that if I call MyAction2 on the next request, the TempData value will be deleted. But if I call other action, not MyAction2, on the next request, will TempData be deleted? If it will be, is there any trick to make sure it exist until the end of the session?

Thanks all.