一见如故的英文：
[Literal Meaning]
one/see/like/old friend
to feel like old friends at the first meeting

[解释]
故：老朋友。初次见面就像老朋友一样。形容初次相见就很合得来。

[Explanation]
to become acquainted soon

[例子]
虽然从来没有见过面，但两人一见如故，很快就熟悉起来。

[Example]
Although they have never met each other before, they became acquainted and familiar soon.

[英文等价词]
hit it off

My brother and my boyfriend hit it off right from the start.
我哥哥和我的男友两人一见如故。

Even after meeting only once, they felt a kinship.
他们虽然只见了一面，但已是一见如故了。

John and Mark hit it off as soon as they met and now they're very close friends.
约翰同迈克一见如故，现在他们是好朋友。

Even after meeting only once, they felt a kinship
他们虽然只见了一面, 但已是一见如故了

They clicked immediately. They loved the same things.
他们随即一见如故，两人的很多爱好都相同。