03/14/2011 12:08 pm ET | Updated May 25, 2011

Ryan Phillippe: Father To Alexis Knapp's Child?

Ryan Phillippe has a brand new relationship, but it's an old flame that may be charging back into his life.

Alexis Knapp, the model/actress who dated Phillippe until they split in September, is in her second trimester of pregnancy, a source close to Knapp told Us Magazine. Another source tells the magazine that she's told friends that Phillippe is the father, though the source close to Knapp wouldn't comment on the father speculation.

An insider close to Phillippe told People Magazine that "Ryan is aware of the situation [and] totally prepared to take responsibility should the child be his." It would be the actor's third child; he has two, Ava and Deacon, with ex-wife Reese Witherspoon.

Currently, Phillippe is not so secretly dating Amanda Seyfried -- he kinda sorta admitted it to Ellen DeGeneres, and she told Elle Magazine that they've, umm, "been seen together."