Grogan will appear in Journey Bound, a film that tells the story of a young lawyer chasing the love of his life through the Scottish Highlands.
The actress, who has also appeared in Red Dwarf, Father Ted and Skins, joins Ford Kiernan, whose involvement in the project was confirmed in November 2013. Award-winning cinematographer John Rhodes and musician Gordon Dougall are also working on the film.
The film is due to start shooting next year if the project can secure its funding.
Ryan Hendrick, the BAFTA nominated filmmaker who's producing the indie flick, said: "I am over the moon to have Clare on board, she is a fantastic personality and really is on the same page. She understands what we are trying to accomplish and she loves the script, which is great to hear.
"It's fantastic that such esteemed and talented professionals are wanting to be involved in this project as they all understand what we are trying to achieve and most importantly why this needs to be done.
"This film is about revitalising the Scottish film industry which is currently on its knees. There are many reasons for this and the lack of trust the industry has for both the audiences and our talented artists being able to produce fun family films for cinema release is at the heart of the problem. We need to fix this."