The couple are reported to have had a secret seven hour rendez-vous at the 'X Factor' judge's London hotel on Monday night, where the Formula One driver was caught sneaking out at 3am.
And he probably would have managed to go undetected if his car hadn't have broken down. Can't a Formula One driver get a pit stop when he needs one, eh?
A friend of the couple told The Sun: "They were determined to keep the meeting under wraps, which is why they chose a hotel that isn’t used much by celebrities.
"Nicole will be livid Lewis’ car broke down because that’s what meant their cover was blown. He had to get out to let the mechanics sort out the issue.
"There’s something that keeps pulling them back together. Lewis even took his dog Roscoe so Nicole could see it."
The couple had been together on-and-off for five years before they split again in July.
Lewis hinted that he was hoping for a reunion in an emotional outpouring on Twitter, soon after their break-up.
"If you’ve found that special some-one, don’t EVER let them go no matter what!!" he tweeted. "Nothing in this world is more important."
He earlier revealed that his split from Nicole had 'turned his world upside down' in a subdued interview with Sky Sports.
However, Nicole seemed to pour cold water on his hopes of a reunion when she told The Sun in August: "The truth is we're no longer together. It is over.
"I know he's been very public about trying to get me back, but we're still not together."