Noah Wyle has become a father for the third time

A spokesperson for the 44-year-old actor said mother and baby are doing well, while Noah - who also has son Owen, 12, and daughter Auden, nine, from his first marriage to Tracy Warbin - is "over the moon" with the new arrival.

The couple first revealed they were expecting a baby when they attended the Vanity Fair Oscars after-party in February, where Sara's bump was clearly visible, prompting their representative to then confirm the news.

Noah and Sara married in a secret ceremony at their ranch in Santa Barbara, California.

Noah said at the time: "It [the wedding] was beautiful. It was great. It was a very small ceremony--we have this little farm in California."

Noah and Sara, who previously had small roles in 'Nip/Tuck' and 'Californication,' met during a production at The Blank Theatre Company in Los Angeles in 2011 and got engaged two years later.

And though he has a new wife, the former 'E.R.' star has remained on good terms with Tracy, whom he split from in 2009 before divorcing her a year later.

The former couple have reportedly remained on good terms since their divorce for the benefit of their young children.

An insider said: "They're cooperative with each other and have put the interests of their children ahead of anything else."