* TheCastShowOff: The actors playing the Commitments were mostly chosen for their musical talents.
* CastTheRunnerUp: Robert Arkins (Jimmy Rabbitte) has auditioned to play Deco before he was cast as Jimmy. He gets to demonstrate his singing in the movie's opening song, a cover of Roy Head and the Traits' "Treat Her Right," and in a cover of Clarence Carter's "Slip Away" in the soundtrack album.
* CreatorBacklash: A mild example, but Roddy Doyle dislikes the scene of Steven going to confession and mixing up Marvin Gaye and Percy Sledge, added by Clement and La Frenais, because it was unrealistic for someone Steven’s age to go to confession, and it was exactly the kind of stereotypical [[{{Oireland}} uber-Catholic Oirish]] trope the book was [[DefiedTrope written to defy]]. He concedes [[ActuallyPrettyFunny the actual joke is pretty funny though.]] He disliked Joey’s mother’s holy statues for the same reason.
-->'''Doyle:''' “The punch line itself was very funny, but he wouldn’t have been going to Confession. That’s much more important.”
* DawsonCasting: Inverted in the case of Andrew Strong, who played Deco. He was sixteen when ''The Commitments'' was filmed but was selected for the role because his singing voice sounded older. One of his anecdotes in the DVD "Making of" featurette involved a listener estimating his age as more than twice that based on his voice alone.
* {{Defictionalization}}: Members of the cast/band have toured under the Commitments name from time to time for kicks.
* {{Irony}}: Johnny Murphy plays Joey Fagan, the most talented and most experienced member of the Commitments. But he's the only one who [[http://www.telegraph.co.uk/culture/culturenews/10341635/Whatever-happened-to-The-Commitments.html didn't know how to play a musical instrument]] in real life.
* WhatCouldHaveBeen: The film-makers considered getting Rory Gallagher or Music/VanMorrison to play Joey Fagan; Morrison was interested until director Creator/AlanParker rejected his condition for taking the role, specifically that he would get some of his own songs in the soundtrack.
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