Nicole Scherzinger arrived back in London yesterday for the first time since Lewis Hamilton's now infamous hotel party.

And reports suggest the high-profile couple's relationship could be hanging in the balance.

The former Pussycat Dolls star reportedly spoke to Hamilton during a series of angry transatlantic phone calls after the late-night bash made headlines.

Now she's back in the UK for the boot camp phase of The X Factor, and is said to be ready for a showdown with the racing driver.

According to the Sunday Mirror, Nicole is still "absolutely livid" over the Formula One star's "disrespectful attitude" to their relationship - and is apparently considering ending the romance.

The paper quotes an unnamed source as saying: "Nicole has been humiliated and she's not going to be a pushover.

"To say she is livid is an understatement. She's not sure there's any point continuing with the relationship and believes his heart isn't in it."

The source went on: "What kind of idiot in the public eye humiliates their girlfriend like that, especially someone as beautiful and successful as Nicole? Lewis's behaviour this week could be the final nail in the coffin."

The on/off couple briefly parted company last year but are thought to have reunited on New Year's Eve.