Shannen Doherty, who originated the role of the bookwormish and bulimic Heather Duke in the dark 1988 cult comedy, “Heathers,” has signed on to appear in TV Land’s television reboot, Variety reports. The actress, 45, announced the news on Instagram on Tuesday by sharing a photo of herself in character on the set. “Sneak peek from the #Heathers set . . . jealous much?” she captioned it. The former “Beverly Hills 90210” star was diagnosed with breast cancer in February 2015, and has been publicly outspoken about her health battles. No word was given on what Doherty’s role will be in the pilot, which will take place in the present.