They will also be involved in a year-long project run, being run from the Isle of Skye, which aims to unearth a new generation of screenwriting talent by getting their vision and ideas off the ground.
Seven writers based in Scotland will be teamed up with leading broadcasters and secure a commission to develop their feature film, drama series or comedy idea into a full-blown script.
Senior executives at Channel 4, Sky, the BBC and BBC Alba will be working with the successful applicants to the scheme, dubbed “Sundance on Skye” after being inspired by Robert Redford’s celebrated talent development initiative in the United States.
Each participant will also be matched up with their own dedicated mentor to support and advice them in the run-up to a final week-long residency on Skye in May 2022. The broadcasters will have “first refusal” to take forward their chosen script for production.
Online workshops and masterclasses will be held throughout the year with industry experts, who will also include Normal People director Lenny Abrahamson, Andrew Macdonad, producer of Shallow Grave. Trainspotting and Sunshine on Leith and Nicole Taylor, writer of Wild Rose and The Nest.
Doctor Who and Sherlock showrunner Steven Moffat, Derry Girls producer Caroline Leddy and Killing Eve writer Francesca Gardiner will also take part.
The new initiative has been unveiled by the Young Films Foundation, set up by Skye-based producer Chris Young, who developed the Gaelic drama Bannan on the island after enjoying huge success with The Inbetweeners.
Young, who has previously run week-long residencies for new writers, producers and directors on Skye, said: “This is an extraordinary opportunity for new Scottish screenwriters at a time when there has never been a greater demand for high quality and original film and TV scripts.
"We’re very lucky to have this incredible vote of confidence in Scotland from these broadcasters and are delighted to be joined by such a high quality range of mentors and experts willing to share truthfully their wisdom and insight.
"Skye is such a unique and inspiring place, and we can’t wait to welcome the participants, commissioners, mentors and experts at the culmination of the year-long programme.
"My advice to applicants is to think very hard about their project, because it will be interrogated from every angle by some of the best minds in UK film and TV."
Inverness-born Gillan, who now lives in New York, said: “This is such a wonderful initiative.
"If there was something like that in Scotland when I was there it would have been totally incredible. I’m so glad to be involved and that there’s now this kind of opportunity.”
Gaiman, who has owned a home on Skye for more than a decade, said: “I’m thrilled to be part of this. Skye is so close to my heart.”
Macdonald, producer of a new documentary on Sir Alex Ferguson, said: “When making a film, it is all about the script. The script is what everyone needs to make a decision – how they will act, design, photograph or even direct. It needs to be written on the page.
"That’s why this is so important and why I’m so delighted to be a part of it. The future of Scotland’s film and TV industry depends on terrific initiatives like this.”