The 'X Factor' judge and the Formula 1 star - who split earlier this year - were trying to keep their seven-and-a-half hour romantic rendezvous on Monday night (14.10.13) under wraps, but they were discovered as the driving ace had to call out mechanics to fix his failing motor.
A friend of the couple said: ''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.''
Lewis, 28, is thought to have convinced the 35-year-old beauty to meet up with him in a bid to win her back, and she is said to still be finding their break up tough.
The friend added to The Sun newspaper: ''Nicole hasn't been able to properly operate without Lewis.
''Some days it was a battle for her to even get out of bed.''
Nicole recently insisted her and Lewis' split is to blame for her being so emotional on the latest 'X Factor' series.
She said: ''On the personal side, it has been a hard year for me. I am not a robot and I wear my heart on my sleeve. Music is part of my life and touches me, so I think I've been a bit more emotional. I was obviously going through some stuff internally and I think anyone could relate to that.''
British pop heartthrobs One Direction became a worldwide sensation when they were thrust together on...
Agents K and J work for the Men In Black, an organisation specialising in hunting...