Blake Shelton is "very smitten" with Gwen Stefani.

A source at the party told PEOPLE magazine: "He seemed very smitten. Gwen was giddy and very flirty. They were both happy.

"They held hands throughout the evening but also mingled separately. Blake was a gentleman and checked on Gwen several times. He made sure that she had drinks."

Meanwhile, the mother of three has already introduced the 39-year-old singer to her and ex-husband Gavin Rossdale's three sons, Kingston, nine, Zuma, seven, and Apollo, 20 months.

However, she is reportedly planning to spend Christmas with her ex to give their children the most "normal [holiday] as possible".

An insider shared: "It's very likely they will be together for some parts of it, but Gwen still wants to have the holidays as normal as possible because of her kids.

"So Gwen may do a more traditional holiday with Gavin when their kids open up the presents, but it's clear to her children they are not with each other in any romantic capacity."