By People Staff
Updated September 12, 2008 12:00 AM
Credit: Michael Diamond Desmond/The CW

The father of Kelly’s 4-year-old son Sammy will finally be revealed on Tuesday’s episode of 90210, PEOPLE has learned. And Brenda will be the one spilling the beans!

Brenda (Shannen Doherty) and Kelly (Jennie Garth) will be having a serious conversation about Sammy’s dad when Brenda reveals his name.

In another twist, the show’s executive producer Gabe Sachs told PEOPLE that there’s a “possibility” the baby’s father could appear on a future episode.

Who it could be? So far, Kelly has mentioned she knew him in high school and they have history together. The couple went their separate ways, but hooked up four years ago. Since then, he’s been out of the picture.

In the series premiere, Kelly took a 3 a.m. phone call from Brandon who is now living in Belize. Their late-night talk was interrupted when Sammy walked in. Perhaps another clue?

Sachs and fellow executive producer Jeff Judah already know who they wanted to be the father, and also discussed it with Garth.

He said Doherty and Garth were great about the news and had a lot of fun. “The two of them love being in on secrets,” he said.

Fans will be in on the secret when it’s revealed Sept. 16, 8 p.m. ET on the CW. –Elaine Aradillas

Tell us: Who do you think is the father of Kelly’s son Sammy–Brandon? Dylan? Don’t forget Steve!

Michael Diamond Desmond/The CW