Harry Styles kisses pal James Corden on Christmas Carpool Karaoke

Harry Styles spiced up a special Christmas-themed edition of The Late Late Show's Carpool Karaoke segment by giving host James Corden a kiss on the lips.

Harry was one of a number of stars who appeared in a Christmas themed singalong on Monday's (11Dec17) episode of the CBS show, with guests from 2017 including Kelly Clarkson, Miley Cyrus, Fifth Harmony, Foo Fighters, Bruno Mars, Katy Perry, Pink, Ed Sheeran, Sam Smith and Usher, all having been filmed with James in his car singing lines from holiday classic Santa Claus Is Comin' to Town.

The Sign of the Times singer, 23, gave the British talk show host, 39, a lot more festive love than he expected, however, as he planted a huge kiss on his lips. James responded by saying, "Wow, I did not expect that for Christmas".

Their Christmas kiss follows another romantic moment during Harry's original Carpool Karaoke segment, when he and James sang Lionel Richie and Diana Ross ballad My Endless Love together while staring into each other's eyes longingly.

"I need to have a chat with my wife," James said after their moment of romance, to which Harry responded, "I need to have a chat with your wife".

The pals go back a long way, as the chat show host met Harry and his One Direction bandmates before they became stars, as he knew Louis Tomlinson's mother from a role she had as a chaperone to kids on one of his TV shows.

As a result, Louis' mom asked James to look after the lads when they were competing as contestants on The X Factor U.K.

"They (the One Direction boys) would come over to our house, and we'd have pizza and play (the soccer computer game) FIFA, and my wife would feel like she was babysitting all of us, and this was before I got married. Harry was at my wedding, and I love him dearly, I love him absolutely dearly, and I'm so proud."

Christmas is certain to be special for James and his wife Julia this year as their third child is due this month (17Dec)

This year's Christmas Carpool Karaoke follows last year's special, when James and his guests joined Mariah Carey to sing her hit All I Want for Christmas Is You.