The publicity-shy pair, who've been together for four months now, were only sprung as lovers when paps snapped them pashing on holiday - a source has told Page Six that they managed to keep it all hush-hush for ages before that!
"They'd been keeping it under wraps and hiding out together on their dates," said the source. "Then Jen realized it wasn't just a fling and decided to take it public."
She was probably playing it safe in case John dumped her ass like he did to Jessica Simpson! Hell, can't blame a girl for looking out for herself.