He tells MTV News, "I did it in the lobby of the theatre in front of the wardrobe. All the employees and people around were clapping. It was super funny.
"I was really nervous and could barely get the words out, which made the situation even funnier."
The couple met earlier this year (05) on New Found Glory's Back To Basics Tour. While they've yet to set a date for their wedding, Gilbert says they're planning to exchange nuptials after their bands complete the touring cycles for their respective new albums, which are both due next year (06).