Born in Pausula (near Macerata), Italy, a local doctor castrated him at the age of eight as treatment for a cough and high fever.
Velluti's father, who had planned on a military career for his son, enrolled him in musical training.
He became close friends with Luigi Cardinal Chiaramonte, the man who would become Pope Pius VII, after singing a cantata sometime in his teenage years.
The last great castrato roles were composed specifically for him: Arsace in Rossini's Aureliano in Palmira (1813) and Armando in Meyerbeer's Il crociato in Egitto (1824).
In 1826 he took over management of The King's Theatre in London and appeared there in Aureliano in Palmira and Morlacchi's Tebaldo ed Isolina.