Although the singer "had an unusually brilliant and flexible upper register, particularly from top F to B flat",[3] Gluck did not like either his expression or his acting ability,[4] but he was obligated to entrust the company's principal tenor with the amatory leads in the operas he was going to produce.
And, if you can, realise this pain inwardly, spiritually, and as if it came from the heart.Nevertheless, Legros submitted himself to Gluck's rude coaching without protest and proved able to profit by it: at the premiere he turned out a quite new performer, to the Parisian musical circles' great surprise.
For his part, Friedrich Melchior von Grimm, who was no such a Gluckist supporter, wrote it was difficult not to regard the metamorphosis of Legros "as one of the most prominent miracles wrought by the enchanter Gluck".
[7] During the following nine years, he appeared in all the French operas by Gluck, taking the roles of Admetus in the 1776 revision of Alceste, Renaud in Armide, Pylades in Iphigénie en Tauride and Cynire in Echo et Narcisse.
[8] When in 1783 Legros was finally granted permission to retire with a pension of 2,000 livres,[8] he was a member of the committee of artistes which had been charged with the management of the Opéra since the former director Antoine Dauvergne's resignation in 1782.
[9] Denis-Pierre-Jean Papillon de la Ferté, the long-serving sole Intendant of the Menus-Plaisirs du Roi, who was ultimately in charge of the theatre, referred to Legros in commendatory terms: he was "the first singer of the Opéra" and his departure "would be a real loss for the administration".