Halle Berry was cast but dropped out, and she was replaced by Katherine Heigl. Berry dropped out due to a custody battle with her ex-partner. After the custody battle was resolved, Berry was re-cast in the movie, but in another role.

Jake T. Austin and Abigail Breslin had to kiss each other more then fifteen times to get the scene right.

When Kaminsky (Hector Elizondo) arrives, the message over the radio announces that "the eagle has landed." This is the same code phrase Elizondo uses in The Princess Diaries (2001) in reference to Queen Clarice (Julie Andrews).

This film was announced as some kind of continuation for Garry Marshall's holiday themed Valentine's Day (2010). The project evolved into a different entity, re-casting some of the protagonists in different roles.

This was the eighth film where Cary Elwes played a doctor.

Lea Michele portrayed one of Jon Bon Jovi's back-up singers in this movie. In 2010, she unintentionally almost hit him with a car once while she was reversing on Robertson Boulevard.

When Claire (Hilary Swank) hands the duties off to Kominsky (Hector Elizondo), she whispers in Chris "Ludacris" Bridges' ear, "Watch him like a hawk." In The Princess Diaries (2001) (in which Elizondo also starred), Queen Clarice (Julie Andrews) whispered the same line to Charlotte (Kathleen Marshall) during Mia's makeover by Paolo (Larry Miller).

Garry Marshall's regular cameos include his daughter, Kathleen Marshall, his sister, Penny Marshall, Hector Elizondo, Larry Miller and Joel McCrary.

In this movie, Matthew Broderick played Mr. Buellerton, while in Ferris Bueller's Day Off (1986), he played Ferris Bueller.

Halle Berry and Michelle Pfeiffer have both played Catwoman in unrelated films. Anne Hathaway, who appeared in Valentine's Day (2010), also played Catwoman.

Reese Witherspoon was offered a role, but turned it down.

Zac Efron and Michelle Pfeiffer appeared in Hairspray (2007).

Sarah Jessica Parker (Kim) and Matthew Broderick (Mr. Buellerton) are real-life husband and wife.

Juliette Binoche turned down the role of Ingrid.

Shipped to theaters under the code name "Last Romance."

Michelle Pfeiffer and Robert De Niro appeared in Stardust (2007), The Family (2013), and The Wizard of Lies (2017).

The groom at the beginning of the film is played by ex New Kid On The Block Joey McIntyre. In the gag reel, Sam, played by Josh Duhamel, jokes that "now that you guys are married, I expect to see some new kids on the block." Joey then turns to look into the camera and asks if they're allowed to say that.

Even though the film has a scene which takes place in the Brooklyn Museum, the museum has no kitchen.

In Hailey's room, there is a drawing of a bike and a souvenir license plate that says "Paul," foreshadowing that Paul is her uncle.