Actress and eco-activist Daryl Hannah has been arrested again in Washington, D.C. after taking part in a protest against the construction of a highly controversial oil pipeline.

The Splash star has been a vocal opponent of the Keystone Xl project, a pipe designed to transfer crude oil from Canada to refineries on America's Gulf Coast, and she joined demonstrators from campaign groups Sierra Club, and Committed Citizens to participate in the civil disobedience action in a bid to get U.S President Barack Obama to abandon the pipeline and move towards a cleaner energy source.

She posted photos of herself at the protest with lawyer and fellow green advocate Robert F. Kennedy, Jr. on on Wednesday morning (13Feb13), but soon afterwards they both found themselves in handcuffs.

A total of 48 campaigners were arrested after refusing to unchain themselves from the gates of the White House following repeated requests by law enforcement officials.

Hannah was subsequently released from custody, and alerted fans to the development, tweeting, "Fresh outta jail & going to visit my hero Lester Brown (a prominent environmental analyst)".

It was the actress' third such arrest since she started protesting the pipeline - she was busted in Texas in October (12) and previously clashed with police outside the White House in August, 2011.