Before lawsuit, Girgenti had approached Kourtney

Model Michael Girgenti, who has claimed that he is the father of Kourtney Kardashian's son Mason, is said to have asked the socialite to take his DNA test as proof, before he filed a lawsuit against her.

Girgenti is said to have written an emotional letter to Kourtney before filing a paternity lawsuit against the reality TV star, reports radaronline.com.

In the note dated April 23, he wrote: "My attentions (intentions) are not to hurt the family you've created with Scott. But at the same time, Mason deserves to know the truth.

"I assure you I don't take being a father lightly. I will be a great father to Mason. Please take this final request for a DNA test seriously because if you don't, I will be forced to take legal action and sue."

Girgenti filed paperwork at the Los Angeles County Superior Court last week in a bid to get joint custody of three-year-old Mason. A hearing has been set for next month.

The model now wants the judge to order DNA tests for Kourtney, Mason and her long-term boyfriend, Scott Disick, 30.

However, the "Keeping Up with the Kardashians" star insists there is no way Girgenti is Mason's biological father as they never had sexual intercourse.