Kate Bosworth was a guest judge on the season premiere of 'Project Runway' last night (18.07.13).

The actress-and-model joined regular panellists Heidi Klum, Nina Garcia and Zac Posen to help pick the best catwalk outfit on the Season 12 launch episode, which tasked a new crop of budding fashion designers with creating a fashionable outfit from a grass-stained parachute.

It seems the 30-year-old star was impressed by the resulting designs, exclaiming how much she enjoyed her time on the show.

She wrote on Twitter: ''Don't miss tonight's premiere of @ProjectRunway on @lifetimetv at 9pm ET ... Loved being a guest @Zac_Posen @heidiklum @ninagarcia @TimGunn (sic)''.

Explaining the bizarre challenge, Heidi - who also hosts and produces the reality competition - told JustJared.com: ''We shot outside of Manhattan and there are 16 skydivers with beautiful parachutes coming down.

''The designers have to run and grab a parachute and design an outfit out of parachute material. I love it when we use unconventional materials.''

Kate looked effortlessly chic in a black mini dress with her luscious locks draping her shoulders as she scored the designs coming down the runway.

The star follows in the footsteps of fellow celebrity guest judges who have sat on the 'Project Runway' panel, including Nicole Richie, Victoria Beckham, Sarah Jessica Parker and Eva Longoria.

Other stars who will join Heidi this season include Kelly Osbourne and actress Kaley Cuoco.