let (one) in on (something)

let (one) in on (something)

To give one information that is private or not widely known, or to include one in something. All right, I'll let you in on what’s really going on here—we're planning a surprise party for Carla. I can't believe Tim let me in on the special offer he got.See also: let, on

let in on

Allow someone to know about or participate in something, as in I'm going to let you in on a little secret. This idiom was first recorded in 1904. See also: let, on

let (someone) in on

1. To reveal (a secret) to someone: They finally let me in on their plans.2. To allow someone to participate in (something).See also: let, on