By People Staff
Updated July 26, 2010 01:00 AM
Credit: Celebuzz

It’s a true sister act!

Reality star Khloe Kardashian posted a photo of herself with her sister Kim and AnnaLynne McCord on the set of 90210 Monday.

“It was such an honor to guest star on a hit show that so many tune in to every week!!” she wrote in a post on her Web site. “We played exaggerated versions of ourselves which obviously wasn’t too difficult to do but we were both still a little nervous.”

Though Khloe writes that this is her first acting gig and “memorizing lines is not really my thing,” she could have gotten some advice from her sister, who’s appeared on other TV dramas like CSI:NY, or from her new friend. “AnnaLynne McCord was sooo sweet,” she says, “she really made it fun and easy for us.”

The sisters will be on the season 3 premiere of 90210 in September, when the show returns on a new night – Mondays. –Aaron Parsley