Lambert originally tweeted Sunday, Dec. 30, that the Tom Hooper-directed film was "visually impressive with great emotional performances. But the score suffered massively with great actors pretending to be singers."
His major complaint was that the film used live-singing rather that studio-recorded performances, which he argued could have "sweetened the vocals."
Lambert's comments even attracted the attention of the film's star Russell Crowe, who tweeted Jan. 1, "I don't disagree with Adam. Sure, it could have been sweetened. Hooper wanted it raw and real, that's how it was."
Lambert tried to clarify his bad review on Tuesday, Dec. 2, by giving the film a few more compliments.
"My movie review has gone viral," he wrote. "You can spend a whole year praising artists for inspiring work, but one critique gets all the attention. Funny."
"Those raw and real moments when characters broke down or were expressing the ugliness of the human condition were superb," he explained. "However . . . My personal opinion: there were times when the vocals weren't able to convey the power, beauty and grace that the score also calls for."
"I guess I'm a purist for the original live broadway recording when the actors sang the f--k out of those songs," he continued. "Just an opinion . . . I should probably stop fanning the flames on this one . . . but I love a good debate- couldn't help myself."
And for his final thought, Lambert added, "One last thing though: Anne Hathaway was so good -- had me tearing up. Oscar-worthy performance for sure! Ok. Done discussing Les Mis."