lips are sealed, his/my

my lips are sealed

I will not tell anyone; I will keep this a secret. A: "Please don't tell anyone about this, I'm so embarrassed." B: "My lips are sealed."
See also: lip, seal

My lips are sealed.

Fig. I will tell no one this secret or this gossip. Mary: I hope you don't tell anyone about this. Alice: Don't worry. My lips are sealed. Bob: Don't you dare tell her I told you. Bill: My lips are sealed.
See also: lip, seal

my lips are ˈsealed

(informal, humorous) I promise not to tell your secret: Don’t worry, I won’t tell anybody. My lips are sealed.
See also: lip, seal

(one's) lips are sealed

Used to indicate that one will not disclose a piece of information.
See also: lip, seal

lips are sealed, his/my

He/I will keep this secret. Although the idea of keeping one’s mouth tightly shut is much older and sealing up someone else’s lips dates from the late 1700s, this particular expression became current only in the early twentieth century. It was much repeated by Prime Minister Stanley Baldwin when asked about the rumored abdication of King Edward VIII, who wished to (and eventually did) marry a divorced American, Wallis Simpson. See also mum's the word.
See also: lip