Lambert, who claimed that his expectations for musicals are "quite high," gave his review of the star-studded film on Dec. 30 via Twitter.
"Les Mis: Visually impressive w great Emotional performances," he tweeted. "But the score suffered massively with great actors PRETENDING to be singers...it's an opera. Hollywoods movie musicals treat the singing as the last priority. (Dreamgirls was good)."
Following his critiques, he added, "Anne Hathaway as Fantine and Enjolras were the exceptions for me. Helena B Carter and Sasha B Cohen were great too. And I do think it was cool they were singing live- but with that cast, they should have studio recorded and sweetened the vocals."
He continued, "Eponine's voice was cool too... I felt like I should ignore the vocals and focus on the emotional subtext- but the singing was so distracting at times it pulled me out. The industry will say 'these actors were so brave to attempt singing this score live' but why not cast actors who could actually sound good? Sorry for being so harsh but it's so True!"
The cast of the film recorded all of their singing live during filming, listening to piano accompaniment through a hidden earpiece. A 70-piece orchestra later gathered in London to record the full orchestrations that are featured in the film and on the soundtrack.
When the tweets were brought to the attention of Oscar winner Crowe, he replied, "I don't disagree with Adam, sure it could have been sweetened, [director Tom] Hooper wanted it raw and real, that's how it is."
As previously reported, the film came in third place in the Dec. 31 domestic weekend box-office results and has grossed over $116 million worldwide.