A mystery diner's good deed has the LAPD Valley Traffic Division smiling.

When it came time for the settling the bill, the waiter said no need -- it's already been paid.

An anonymous patron treated the officers to lunch Friday evening, leaving a note.

"It is my pleasure to buy you lunch," the note read.

Our Offcrs were out 4 lunch their server handed them a note &told them that someone paid their lunch.The note read

(TY from all of us)#LAPD pic.twitter.com/ngXkml6ccD — LAPDValleyTraffic (@LAPDVTD) October 19, 2016

The officers were so thankful for the kind gesture that they posted the note to their Twitter account as a public thank you.

The note-giver stated the reason behind their anonymity was to prevent anyone from saying it was to curry favor.

"P.S., I'm truely sorry for the loss of all law enforcement," the note also read.