start command at given time interactively in terminal

is there similar command to sleep, but where I can specify given time, so that my command will start at given time, **INTERACTIVELY** in my current open terminal window? I know about at command, but that would not work as it does not run interactively in my current open terminal window. I need to start my command at 04:00 in my terminal, as if I woke up, typed my command, and pressed enter. The closest solution I can think of, is to calculate before I go to bed, how many seconds remain until 04:00, and use sleep command. But that is so ugly. There must be a better way to do this.