Britney Grows and So Do Her Agents' Frustration

5/2/2006 11:50 AM PDT

Agents don't like to learn things about their celeb clients from the tabloids, and they especially don't like to find out that their biggest client -- whom they've been selling all over town for feature film roles -- is pregnant.

"Frustration" is a word being used around the offices of William Morris, the agency that reps Britney Spears. "It came as a shock," said one insider.

Spears' agents have become increasingly frustrated about how to handle America's favorite popstar. "She doesn't need the money. So there's not the usual desperate drive on her part," the source said. "She's constantly changing her mind. One minute she wants to be an actress, the next minute she wants to fly to Maui to record a new album."

A W.M. employee told TMZ: "It seems like she's not sure she knows what she wants to do, which makes being her agent frustrating."

People in the agency are saying that Spears' pregnancy has derailed a lot of plans. Sources say now that Spears is pregnant she's not pursuing her acting career with the same fervor, even scuttling her bid to land the role of a lifetime -- playing Janis Joplin. One source said: "She really wanted to do it but she knows she can't."

We're told the Joplin role was offered to Lindsay Lohan but she passed, and now producers are eying Kate Hudson.