Kutcher's cheating to end six-year marriage?

One of Hollywood's biggest celebrity unions could be about to come to an end amid rumours of persistent infidelity.

New 'Two and a Half Men' star Ashton Kutcher allegedly spent 23 September with a younger woman at Flux nightclub, San Diego, radaronline.com reported.

Perhaps for 48-year-old Demi Moore, the latest rumour about Kutcher's infidelity has been the final straw, particularly as the rendezvous occurred on the eve of the couple's wedding anniversary.

According to the site's sister publication, Star Magazine, an insider said: "It was definitely a long time coming, but they're finally done for good.

"Ashton was a serial cheater, and Demi just couldn't take it anymore. She didn't deserve to live that way."

The site also suggested the couple, famed for their large age gap, have been living apart for some time.

Kutcher's big Hollywood break came in 1998 when he starred as Kelso in popular TV hit 'That '70s Show'.

The handsome actor dropped out of the University of Iowa, where he was studying biochemical engineering, to pursue a career in modelling.

From there, his on-screen success shot him to stardom.