be right there
To be very close to arriving at the location of the listener (or recipient of the message). It typically indicates that one is actively en route, and can be used as a standalone set phrase. I'm around the corner, so I'll be right there. I hear you knocking. Be right there!
(I'll) be right there.
I'm coming. Bill: Tom! Come here. Tom: Be right there. Mother: Can you come down here a minute? Child: I'll be right there, Mom.