Wearing a Zac Posen dress and Sergio Rossi shoes, Cameron Diaz returned to the red carpet smiling at the L.A. premiere of her new comedy, What Happens In Vegas, on Thursday.

It was her first public appearance since her father's untimely death last month.

She and co-star Ashton Kutcher played to the crowd: Half the fans in the bleachers were wearing "Team Ashton" shirts, the other half were wearing "Team Cameron" shirts.

They asked fans to compete by yelling the loudest. Each actor cheered on their teams.

Leave it to Diaz to put on such a brave face after her father's passing, her co-star Jason Sudeikis told Usmagazine.com.

"She is really sweet,” he said.

Added pal Lake Bell, “If it was you or me or anyone else here, I would just respect their privacy and that’s kind of how I’m doing it, but of course, I send my blessings.”

Diaz skipped out on a weekend press junket for What Happens In Vegas (out May 9) to be with her family. Kutcher read a letter to her fans, where Diaz said she planned to screen the comedy for her grieving family.

"It was a unanimous decision that we all needed to share a good laugh," she wrote. "After all that's why we make films like these. So people can leave behind their worries for a couple of hours."

Diaz's father, Emilio, passed away at age 58 of post-influenza MRSA pneumonia on April 15.

In a statement, the actress told Usmagazine.com: My dad was loved by so many people and his humor and spirit will always live on in our hearts."