well-kept secret
best-kept secret

I will now let you in on a well-kept secret.

He was more than happy to consider himself a well-kept secret.

"What we had going on there was pretty much a well-kept secret until then."

But if any investigation took place, it was a well-kept secret.

City Airport is no longer the well-kept secret it once was.

This is such a well-kept secret - how come nobody knows about it?

For the most part, they say, the village is a well-kept secret.

He points out, however, that the location of Area 51 was not a particularly well-kept secret.

For the fashion world, it was a pretty well-kept secret.

And the reason it’s managed to remain a well-kept secret?

That piece of wisdom appears to be a well-kept secret.

The exact nature of these movies is a well-kept secret.

Did we spoil a well-kept secret or make a bad call?

Canada's well-kept secret is being brought out of the closet.

Alter may have been right, but if so, it was a well-kept secret.

The trail is not always clearly marked, and seems to be a well-kept secret.

If any evidence exists to support this theory, it has been a well-kept secret.

But the exact place of the purple must be a well-kept secret.

She says with a smile, "They feel like that they've found a well-kept secret."

Cosmetic surgery is no longer the well-kept secret of a few.

What may not have been a terribly well-kept secret still felt unexpected.

But in spite of this good press, Canada remains for many a very well-kept secret.

King's decision, though a well-kept secret, was little surprise, as most observers had expected him to find common cause with Democrats.

Waskesiu has been a well-kept secret from the rest of the world.

You're just going to have to remain the best-kept secret in town.

Sometimes I think we just want to remain the best-kept secret in the world.

Work was at the same time absolutely central to our lives and yet the nation's best-kept secret.

For months it has been the best-kept secret of European business.

For those of us who love Thailand’s best-kept secret, that is just fine.

Apparently what was thought to be the best-kept secret of the Games is out.

God knows it's not the world's best-kept secret in the first place.

For years he has been one of Texas's best-kept secrets.

Here is one of the best-kept secrets about doing business in Japan.

That children with physical problems such as this are one of medicine’s best-kept secrets?

I believe a career in a tech field is the best-kept secret for girls.

It was, for a while, the best-kept secret in Washington.

"I believe this treatment is one of the best-kept secrets ever."

The dress has been the best-kept secret of this very public event.

But there was one way she surely could not have learned, the best-kept secret.

"We got tired of people telling us we're the best-kept secret in Texas."

Yet in some ways it remains the best-kept secret on Broadway.

But the decision to play in the regular season became one of the league's best-kept secrets.

I wanted to avoid people because it's the best-kept secret in the world, isn't it?

I thought my real place was one of the best-kept secrets in the galaxy.

The Brotherhood has been one of the best-kept secrets in the world.

She might also be just about the best-kept secret.

Nina is just about the best-kept secret in this hemisphere.

For most of the spring, it was the best-kept secret in the Yankee camp.

IF you come closer, we will whisper one of the political season's best-kept secrets.