On Saturday, September 22, photographers in New York noticed that the 24-year-old comedian had the words "mille tendresse" drawn on the back of his neck, with the design appearing to be a near exact copy of a tattoo Ariana had done in 2014.
Meaning "a thousand tendernesses", the words refer to a line spoken by Audrey Hepburn in 1961 movie "Breakfast at Tiffany's".
The Oscar-winning actress, who played Holly Golightly in the iconic romantic comedy, says: "Bless you, darling Fred. Please forgive the other night. You were an angel about the whole thing. Mille tendresse."
Pete and Ariana, who began dating in May and got engaged weeks into their new romance, already have matching tattoos.
Both are inked with the number 8418, which is the badge number worn by Pete's father, New York City firefighter Scott Davidson, who died during the September 11 terrorist attacks in 2001.
The "Saturday Night Live" star has the numbers inked on his left forearm, while the "No Tears Left to Cry" hitmaker has hers on her left foot.