Perhaps enough to be let in on the big secret.

It's not a big secret as to what their relationship is like.

"Are you ready to let me in on the big secret now?"

But now there is a big secret between them, he said.

Is that the big secret I can see in the back of your eyes?

Is it time for me to know that big secret now?

She looked just like a kid with a great big secret.

"What is it they think should be such a big secret?"

He had never let anyone in on his biggest secret.

Four years ago the Commission's working groups were a big secret.