Ryan Phillippe was reportedly by his ex-girlfriend's side as she gave birth to a baby girl last week.
Alexis Knapp gave birth to baby Kai weighing 8lb, at Cedars-Sinai Medical Centre in Los Angeles on July 1, In Touch magazine reports.
The Cruel Intentions star and the 26-year-old actress were not a couple when news broke of her pregnancy in March and the paternity of the child is currently unknown.
But Ryan has been involved with the pregnancy, and he and Alexis have been spotted together several times in the last few weeks.
The Lincoln's Lawyer star - who is already father to daughter Ava, 11, and seven-year-old son Deacon with his ex-wife Reese Witherspoon - split from Alexis in October 2010.
Shortly afterwards Ryan was linked to Amanda Seyfried but the pair have since split.
Alexis has had minor roles in romantic comedy Couples Retreat and children's adventure Percy Jackson & The Lightning Thief.
She will appear alongside Miley Cyrus in her new film So Undercover.
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