The hilarious incident unfolded when Oswalt, who was hosting the ceremony in Los Angeles, admitted he was going to wait to take aim at U.S. president Donald Trump "because I don’t want to be kicked to death by James Woods backstage."

Once Upon a Time in America star Woods, one of Hollywood's most outspoken right-wing supporters, then yelled at Oswalt: "Buy a pair of shoes!"

At that point, he ran onto the stage and stole one of Oswalt's black sneakers, laughing: "Didn’t you see Crazy, Wonderful Love, or whatever it was called? Get some shoes!"

Woods was referring to the film Crazy, Stupid, Love in which Ryan Gosling's character helps Steve Carell's buy some less ugly footwear.

Oswalt later took to his Twitter page to hit back at claims the moment had been a set up, writing: "It wasn't staged, believe me".

Woods also commented on the incident on his social media, writing: "@pattonoswalt knocked it out of the park tonight at the @WGAWest Awards. And I stole his shoe! #UnplannedComedyMayhem He's seriously great!"

The moment didn't otherwise detract from what was a successful evening for stars including Donald Glover, who scored a double win at the ceremony when his hit TV series Atlanta took home the Best New Series and Best Comedy Series gongs.

Arrival, This Is Us, Sesame Street, and The Unbreakable Kimmy Schmidt were also among the winners at the Writers Guild Awards.

Amy Adams' sci-fi film was named Best Adapted Screenplay, This Is Us picked up the Episodic Drama prize for The Trip, while Kimmy Goes on a Playdate! was a winner in the Episodic Comedy category.

Sesame Street's Once Upon a Sesame Street Christmas took home the Children's Longform trophy.

Other early winners included General Hospital (Daytime Drama), American Crime Story: The People vs. O.J. Simpson (Longform - Adapted), Confirmation (Longform - Original), Hollywood Game Night (Quiz & Audience Participation), and Triumph The Primary Election Special 2016 (Comedy/Variety Special).

The awards were handed out during simultaneous ceremonies in New York and Los Angeles, with the Manhattan ceremony hosted by comedian Lewis Black.

Special honourees saluted during the prizegiving included Oliver Stone, Aaron Sorkin, Richard Curtis, late Iranian filmmaker Abbas Kiarostami, and Dan Wilcox.

The main list of winners at press time were:

Original Screenplay

Moonlight (written by Barry Jenkins, Tarell MCCraney)

Adapted Screenplay

Arrival (Screenplay by Eric Heisserer)

Documentary Screenplay

Command and Control (written by Robert Kenner and Eric Schlosser, Brian Pearle and Kim Roberts)

Drama Series

The Americans (written by Peter Ackerman, Tanya Barfield, Joshua Brand, Joel Fields, Stephen Schiff, Joe Weisberg, Tracey Scott Wilson)

Comedy Series

Atlanta (written by Donald Glover, Stephen Glover, Stefani Robinson, Paul Simms)

New Series

Atlanta (written by Donald Glover, Stephen Glover, Stefani Robinson, Paul Simms)

Longform - Original

Confirmation (written by Susannah Grant)

Longform - Adapted

American Crime Story: The People vs. O.J. Simpson (written by Scott Alexander, Joe Robert Cole, D.V. DeVincentis, Maya Forbes, Larry Karaszewski, Wally Wolodarsky)

Animation

Fish Out of Water (BoJack Horseman)

Episodic Drama

The Trip (This Is Us)

Episodic Comedy

Kimmy Goes on a Playdate! (Unbreakable Kimmy Schmidt)

Video Game Writing

Uncharted 4: A Thief’s End (written by Neil Druckmann, Josh Scherr, Tom Bissell, Ryan James)

Comedy/Variety Talk Series

Last Week Tonight with John Oliver

Comedy/Variety Sketch Series

Saturday Night Live

Daytime Drama

General Hospital

Comedy/Variety Specials

Triumph The Primary Election Special 2016

Quiz and Audience Participation

Hollywood Game Night

Children's Longform

Once Upon a Sesame Street Christmas (Sesame Street)

Children's Episodic

Mel vs The Night Mare of Normal Street (Gortimer Gibbon's Life on Normal Street)

WGA's Valentine Davies Award for Humanitarian Service: Richard Curtis

2017 Jean Renoir Award for International Screenwriting Achievement: Abbas Kiarostami

2017 Morgan Cox Award: Dan Wilcox

Paul Selvin Award: Susannah Grant

Laurel Award for Screenwriting Achievement: Oliver Stone

Animation Writing Award for Lifetime Achievement: Mike Judge

Paddy Chayefsky Laurel Award for Television Writing Achievement: Aaron Sorkin