Christina and her fiance Matthew Rutler have offered to host Hillary's last big fundraiser of 2015 at their home in Los Angeles on 4 November (15), Billboard.com reports.

Many celebrities are expected to flock to the event, which falls shortly after the politician's birthday on 26 October (15). Christina is also expected to put on a special performance, according to People.com.

The pair previously met at an event in 2012, when the singer was honoured for her work as a United Nations World Food Programme Ambassador. Their meeting made the headlines as a picture from the event showed Hillary looking at Christina's cleavage.

"That looks like it was Photoshopped but it's not. It was a real moment," said the singer of their infamous meeting. "She's such a force in a room. She's got that star charisma and everything about her. I couldn't take my eyes off her, either, so it was mutual."