The saying " thick as thieves" means the same thing.

成语" 亲密无间（像贼一样亲密）" 意思也一样。

One of my favorite expressions to describe close friends is to say they are thick as thieves.

我最喜欢的一个描述亲密朋友的表达是说他们thick as thieves（亲密无间）。

If two friends are thick as thieves, they are very close and trust each other a lot.

如果两个朋友亲密无间（thick as thieves），他们非常亲密且彼此十分信任。

They are thick as thieves, those two.

他们两个像小偷一样厚道。

I see you two all the time.You're thick as thieves, you are.

{\an2}你们俩成天粘在一起。

At first it was socially at parties here and there. But the two of them are sort of thick as thieves right now, a Hollywood source says.

起初，他们在各处的社交聚会上见面。但他们俩现在就像小偷一样亲密无间。”一位好莱坞知情人士称。