The pair received four yeses after their original audition on Saturday night, where they performed an Italian opera number.
New judge Alesha Dixon gushed: "It’s not very often that that happens, that you can move an audience like that - You sing beautifully together. It was world class."
Speaking on Daybreak this week, Charlotte teased: “If we get through to the next round, we've already thrown some ideas around... maybe not just the Italian stuff but also a bit of musical theatre.”
And the 16-year-old didn't even rule out a bit of thrash metal if they make the live shows in May!
Jonathan meanwhile described watching his audition back on the TV as "really weird", having been "so nervous" on the day that it didn't sink in.
Charlotte explained: “When we were standing backstage we weren’t speaking.
"We were in complete silence, we didn’t know what to do with ourselves.”
The pair also remained tight lipped over what will happen next, adding: "We have to wait until we find out how the rest of the process is going to go and what’s going to happen.
"We are hoping, so fingers crossed.”
Britain's Got Talent 2012 continues on Saturday night on ITV1.