OMAHA, Nebraska (Reuters) - Steve Martin has released an off-beat ad endorsing Bob Kerrey's candidacy in Nebraska's U.S. Senate race, in which the actor and comedian demonstrates how to build a wad of paper while cue cards offering praise for Kerrey are displayed on the screen.

Martin, playing the role of "home crafts expert," mangles a blank single sheet of white paper with paper clips, scissors, staples, chewing gum and a hammer, while a hand emerges from off screen offering typed messages in praise of Kerrey.

"He is a principled man whom I have known and respected for many years," reads one.

"But most of all... He is sane. And his ideas are workable," reads another.

Kerrey, a Democrat, represented Nebraska in the U.S. Senate from 1989 to 2001, when he moved to New York City to lead The New School university. He returned to Omaha this year to seek the seat of retiring U.S. Senator Ben Nelson, a Democrat. Kerrey, who faces Republican State Senator Deb Fischer in the November 6 election, has trailed in polls.

In a Facebook posting introducing the web video, Kerrey joked he has been aware of Martin's "home crafts expertise," and is "pleased that he now wants to share his talents with you along with his endorsement for me for the U.S. Senate." (Editing by Edith Honan and Vicki Allen)