Generally no. But you can use the AsyncTask function from your thread to push some functionality to happen on GameThread:
void ThisFunctionRunsOnADifferentThread()
{
// Do lots of slow thread stuff here.
int SendMeToGameThread = 1337;
AsyncTask(ENamedThreads::GameThread, [SendMeToGameThread ],
{
// Do whatever you need to do on the gamethread here.
// Use `SendMeToGameThread` or any other variables you created in the thread through the [brackets] above.
});
}