Lewis Hamilton and Nicole Scherzinger (Pic:PA)

IT’S just as well Simon Cowell likes fast cars – he might need to speed off sharpish if F1 race ace Lewis Hamilton claps eyes on him...

McLaren driver Lewis, 26, says the X Factor supremo is one of the key reasons that his four-year romance with Nicole Scherzinger hit the skids.

He reckons 52-year-old Cowell’s decision to offer Nicole, 33, a judging job on X Factor USA – replacing Cheryl Cole – put “immeasurable strain” on the couple’s relationship.

Lewis has been tied up on the Grand Prix circuit while former Pussycat Doll singer Nicole’s own hectic schedule has prevented her from spending time with him on race days.

It means they have barely seen one another in person since May.

Concerned by both their hectic lifestyles, Lewis is understood to have decided they needed a break – as I revealed on Monday.

Last night, a source close to the couple confirmed: “Lewis and Nicole have been having problems for the past six weeks.

“Increasingly hectic schedules this year have meant limited face-to-face time.

“They’ve probably spent more time on the phone or on Skype than they have in person.

“Sadly, Nicole’s job on X Factor USA – which, professionally, has been an unmitigated success – appears to have come at the cost of her relationship.

“Nicole was under enormous pressure to succeed and was desperate to please Simon, her boss.

“But Lewis found their intense working relationship hard to contend with.

“This, plus Lewis’s crazy international jet-set lifestyle, put immeasurable strain on the pair.

“She was crushed and did everything she could to make it work. They are still good friends though and the break-up is all very amicable.”

Multi-millionaire Lewis, who was said to be in a “vile mood” after last weekend’s Korean Grand Prix, recently said he was a long way off wanting to start a family.

Meanwhile, Nicole has become friends with host Steve Jones, who is said to have a crush on her.

Last night, a spokesman for the couple declined to comment.