Clutching glamorous co-star Lea Michele, the young screen star was seen without his wedding ring.
His six-year union with Demi Moore lies in tatters after the 49-year-old actress last month announced she was divorcing her love-rat husband.
Demi called time on the relationship after blonde Sara Leal, 22, said she romped with the Two And A Half Men actor on the couple's sixth wedding anniversary in October.
She said in a statement: "It is with great sadness and a heavy heart that I have decided to end my six-year marriage to Ashton.
"As a woman, a mother and a wife there are certain values and vows that I hold sacred, and it is in this spirit that I have chosen to move forward with my life."
She added: "This is a trying time for me and my family, and so I would ask for the same compassion and privacy that you would give to anyone going through a similar situation."
Kutcher then wrote on Twitter: "I will forever cherish the time I spent with Demi. Marriage is one of the most difficult things in the world and unfortunately sometimes they fail."
But last night, at the gala opening of New Year's Eve at Gramuan's Chinese Theatre in Hollywood, 33-year-old Kutcher successfully hid any pain he may have had because of the split.
He even had a playful peer cosn his co-star's plunging front.
In the romantic comedy he plays the aptly-named character Randy.
The ensemble piece features contributions from a host of Hollywood royalty including Robert De Niro, Halle Berry and Jessica Biel.
Fellow cast members Michelle Pfeiffer and Zac Efron also attended the premiere and posed happily together as did husband and wife Josh Duhamel and Fergie from the Black Eyed Peas.