It was Jamie Lee Curtis who contacted the head of Disney with the idea to make a second film. She persuaded Lindsay Lohan to return to Disney as the two became close friends after the 2003 film.
Anna and Eric's wedding date is October 3rd, the iconic date from Lolita malgré moi (2004), which also featured Lindsay Lohan.
Costume designer Natalie O'Brien tracked down Jamie Lee Curtis' silk paisley dress from Freaky friday - Dans la peau de ma mère (2003). She found the vintage Diane von Furstenberg dress on eBay, and it was about six sizes too small. After a hodgepodge of additional panels, she tailored it to the correct size.
While filming the final concert scene, a real earthquake hit the city of Los Angeles. Cast and crew had to evacuate the set before filming could resume. Things got extra confusing when the director later called out "Earthquake!" for the leading cast to react to due to the scripted earthquake during that scene!