Nicole Scherzinger is reportedly keen for Lewis Hamilton to propose to her following their recent break-up.

The songstress split from the Formula One racing driver in October due to their conflicting work schedules. Nicole and Lewis had been together on-and-off for four years.

It has now been revealed that the pair are on the verge of a reunion, although Nicole has reportedly laid down a few conditions before giving their relationship another go.

"It seems Nicole's told him that if he's serious about getting back together, the only way to prove it is with an engagement ring," a friend told more! magazine. "I'm sure Nicole was devastated when they broke up. She seemed so heartbroken. But she's very strong-willed. I think she pushed through it and has been quite happy in recent weeks."

"[Lewis'] reaction [to Nicole's ultimatum] was really positive," another source added. "I think he wants Nicole back and now he knows what needs to be done, the ball is in his court. I don't reckon Nicole would be concerned with the size of the ring, but knowing Lewis, it will be a serious rock."

Since splitting from Lewis, Nicole has been linked to a string of men including professional dancer Derek Hough, US X Factor host Steve Jones, and rapper Drake.

A friend of Lewis says the sports star was hurt by such reports, but it reignited his feelings for the beauty.

"It seemed like as soon as Lewis thought Nicole was getting over him, he began to realise what he was losing," his friend told the publication.

"I think he really missed having her there as his confidante, supporting him during the racing season. They had a lovely relationship it wouldn't have lasted four years if there wasn't something special going on."