Tina Fey said of the experience: "Oprah is very funny in the episode, and we are beyond grateful to have her. Also, I would like to announce that we are officially best friends."

Which means she achieved her goal. Last April, during the writers strike, Fey said, "I still want Oprah to play my best friend. I feel like I haven't -- I want to spend time with Oprah, and I don't know what I need to do to make that happen."

Oprah's gal pal Gayle King told the New Yorker about Oprah's guest shot: "It is a hoot. It was taped last Saturday. Let me tell you, Tina Fey and Oprah Winfrey together is magic. It's great television. Must-see TV."

"You know her acting skills," Gayle added. "She's an Academy Award nominee! So she has acting chops. But I think the role of Oprah Winfrey suits her best ... Oprah and Tina together: Hilarious. H-I-L-A-A-A-R-I-O-U-S ... Lots of A's. That was done deliberately for emphasis."

At last weekend's Creative Arts Emmys, "30 Rock" won three trophies, and the show is up for six more during the primetime show this Sunday.