A little sis for Lindsay Lohan?

In this April 28, 2008 file photo, actress Lindsay Lohan poses on the press line at the LG Scarlet Series Launch Party in West Hollywood, Calif. [Agencies]

Another chapter has been added to the Lohan family saga – and this time, it may be another Lohan.

Michael Lohan, father of actor Lindsay, acknowledges he once had a relationship with a woman who claims he's the father of her 13-year-old daughter.

But he questioned why she would take the story to OK! magazine, which reported the claim on Friday, without waiting for a paternity test to be done.

"Why would someone without taking a test put something out there like this?" said Lohan. "What if it's negative? What is that going to do to her own child and my children? Is this for the fame? There was correspondence where she said Ashley, her daughter, wants to be an actress, and she's so talented," said Lohan, adding the woman, Kristi Horn, first contacted him about the paternity claim when he was in prison a couple of years ago.

"If I wasn't Lindsay's dad or Michael Lohan, this wouldn't be getting any attention," he added Friday night.

Lohan said he hasn't spoken with Lindsay or any of his other three children about the incident.

Lohan, a former Wall Street broker, is divorced from Lindsay's mother, Donata "Dina" Sullivan. He said his affair with Horn happened when he and Dina were separated.