Mercedes F1 driver Lewis Hamilton is poised to ask Pussycat Doll and X-Factor judge Nicole Scherzinger to marry him, it has been claimed.

According to reports by British tabloid newspaper, The Daily Star, the couple have been back together now for around four weeks, although they have tried to keep it 'top secret'.

"Nicole, 35, has told friends she wants to be 'absolutely sure' before they go public again after several break-ups," reads the report. "But the F1 ace, 28, hopes to prove his commitment by proposing to her in California after Christmas."

"This will be the third time Lewis has planned to pop the question," 'close pals' allegedly told the 'paper. "But he believes this time is different. Both of them have benefited from the split, realising it's impossible for them to be without each other.

"He wants to take Nicole to romantic Carmel and present her with the ring. There's no doubt in his mind she'll say yes."

The report also quotes 'sources' as revealing: "Lewis was doing all the chasing. Nicole only agreed to take him back on the condition that they tie the knot next year."

Earlier this year, Hamilton admitted that splitting with Scherzinger had been difficult and that it was hard for him to put to one side even at race weekends [see separate story - HERE].

"I wear my heart on my sleeve and that gets me in trouble a lot of the time and I generally find it very, very hard to fight my emotions," he explained to Sky Sports F1's Martin Brundle at the German GP back in July. "You have different people who are able to hold in their emotions - I have a Finnish trainer, for example, who doesn't show any emotion and they are always able to control it.

"I'm going through ... I'm trying my hardest to be positive but I'm going through a really, really tough time at the moment with the loss of someone really, really special in my life," he admitted, confirming that he was referring to Scherzinger.

"My world's turned upside down."