The teenage singers, who finished runners-up in the 2012 competition earlier in the month, will release an album in September as originally claimed this morning.
Jonathan Antoine said: "Appearing on the show has been a huge confidence boost and I'm still pinching myself that we are actually making our album."
"Thank you to everyone for making this happen for us," the 17-year-old added.
Cowell, head of Syco Music, commented: "This show is designed to give people like Jonathan & Charlotte an opportunity."
Watch Jonathan & Charlotte's first Britain's Got Talent audition below: