looking for an old cartoon/anime

It's an old show I watched when I was young, but I don't remember if at the time it was new or not, so it's at least 15~20 old but might be older.

It follows a young robot boy who goes on adventures. He's a fan of another celebrated robot, the size of a Gundam, but doesn't realize the other bot is in fact a Mech-suit. There's is a hero sidekick type relationship between the robot boy and the pilot/mech.

That's all I can remember about it

thx !