At the start of the film, as the twins climb out of bed, there’s a shot of their feet on the floor and what appears to be a face under the bed. It’s rumoured to be baseball equipment, but it’s actually the executive producer hiding to see whether directors Bobby Farrelly and Peter Farrelly would notice — they didn’t.
Matt Damon met his future wife Luciana Damon after the cast and crew persuaded him to go out to a pub one evening, where she was working behind the bar.
Ben Carson is a practising surgeon who successfully separated conjoined twins in real life. In a 22-hour operation, he became the first surgeon in history to achieve this with both twins surviving. His wife and their three children are shown in the hospital's waiting area.
Ray 'Rocket' Valliere's speech after the end credits hadn't been planned. He rambled on while the cameras kept rolling. Lunch had already been called and the crew were getting restless. But his remarks were so heartfelt that nobody interrupted him.
When Cher first signed on to appear in the film, her part in the script was simply listed as 'actress'. Directors Bobby Farrelly and Peter Farrelly felt it would be a good idea for Cher to play herself, so they amended the script.
Jim Carrey was at one time attached to the project, while Woody Allen was in discussions to portray the other brother.
The country song played over the end credits is performed by George Schappell, one of a pair of conjoined twins referred to in the film.
Ben Carson, who portrays the surgeon in the film (credited as Benjamin Carson, Jr.), stood for President in 2016.
The distinctive manner in which Greg Kinnear performs "Summertime" towards the end of the film is strikingly similar to the way the late soul singer Billy Stewart delivered the song on his 1966 album "Unbelievable".
Ben Carson, the surgeon who performed the operation to separate Walt and Bob, is depicted in the biopic Gifted Hands: The Ben Carson Story (2009), with Cuba Gooding Jr. in the lead role.
In the homecoming match, the twins, playing for the Martha's Vineyard Vineyarders, thrashed the Nantucket Whalers. The two secondary-school football sides share a fierce rivalry, and many people from Martha's Vineyard were pleased to see the Whalers' defeat shown on screen. Nantucket declined to comment.
The directors wanted April to have very large breasts to emphasise her bimbo character and even considered having the actress wear a pair of prosthetic breasts. But after meeting Eva Mendes, they reworked the role after telling her she had "great breasts".
When the twins first encounter Meryl Streep in the restaurant, they claim to be friends with Timothy Sheehan. Tim Sheehan served as Greg Kinnear's assistant during the making of the film.
Bobby Farrelly appears as one of the brothers wearing goalkeeper pads in the hockey sequence.
Cher has a copy of People magazine's 'Who's Hot Who's Not' issue. The cover's "Hot" section shows Cher alongside actors who had previously worked with the Farrelly Brothers: Cameron Diaz, Chris Cooper, Renée Zellweger, and Gwyneth Paltrow. The sole individual listed as 'Not Hot' is property master Richard K. Wright.
Ricky Williams: appears as the coach in a flashback sequence centred on high-school American football.
Strictly speaking, conjoined twins are invariably identical. If the final stage of embryonic cell division — the process that would normally produce two separate identical twins — does not complete, the twins remain joined and develop connected in the womb in some way.
Bob and Walt's hairstyles and wardrobe are almost indistinguishable from those of Lloyd and Harry in an earlier Farrelly Brothers film Dumb and Dumber (1994), portrayed by Jim Carrey and Jeff Daniels. The most noticeable similarities are the long blond hair and the brown bowl cut.
During Bob and May's first date, Walt mentions Annie Hall (1977), the Woody Allen film in which he suggests they kiss at the start of the date rather than at its conclusion. Minnie Driver made a similar suggestion to Matt Damon in Good Will Hunting (1997).
Dane Cook shot a scene portraying an LAPD officer who stops Bob and Walt, but it was omitted from the film's final cut. The footage appears in the DVD's supplementary features.
This was the Farrelly Brothers' first film shot in Panavision (anamorphic) 2.39:1, a format favoured by director of photography Dan Mindel.
Cher and Meryl Streep had previously co-starred in Silkwood (1983).
The twins' football team go by the name the Sharks, a nod to Jaws (1975), the filming of which also took place on Martha's Vineyard.
Three NFL players make cameo appearances: Ricky Williams, Tom Brady and Lawyer Milloy.
Fernanda Lima: a former VJ on MTV Brasil who portrayed Susie in Honey & The Beaze.
Bella Thorne, Fernanda Lima, Kelly Albanese, Carolyn Stotesbery and Lisa Marie Thomas all made their film debuts.
