Ryan Phillippe and Alexis Knapp
Wireimage; Globe Photos
03/15/2011 at 06:00 PM EDT
As Ryan Phillippe
awaits the results of a paternity test to determine if he is the father of ex-girlfriend Alexis Knapp's unborn baby
, Knapp herself is happily preparing for the birth, sources tell PEOPLE.
"She's doing really well, handling everything and just taking it day by day," a source says of the actress, who dated Phillippe last summer and is believed to be due in June. "She's excited for the baby!"
As for Phillippe, he is keeping a low profile until test results come back, adds another source.
"In all likelihood, Ryan's not doing or saying anything publicly until there's a paternity test that proves he's the father," says a source close to the actor.
And although the pregnancy came as a surprise to the public, "Ryan has known from the very beginning," adds the first source. "As soon as she found out, she told him. She found out she was pregnant while she was filming [her upcoming movie] So Undercover
Phillippe, 36, who has two children with ex-wife Reese Witherspoon
34, has moved on romantically, and was spotted recently cozying up to Amanda Seyfried after the premiere for her movie Red Riding Hood
, as well as at the opening of his The Lincoln Lawyer
Knapp appears in two upcoming movies, Project X
this Thanksgiving and Miley Cyrus
film So Undercover
, also in the fall.