 " Sexy " marked Paltrow 's second guest appearance on Glee as substitute teacher Holly Holliday . She first appeared earlier in the second season , in the seventh episode , " The Substitute " . The role was devised for her by series co @-@ creator Ryan Murphy , who suggested that she showcase her vocal and dancing talent ahead of the release of the film Country Strong , in which Paltrow plays a country singer . Paltrow was signed to Glee for two episodes , with " The Substitute " originally intended to feature a love quadrangle between Holly , Will , Emma and Carl . Her initial arc was , however , reduced to a single episode . Post @-@ broadcast , Murphy said they both hoped she would appear on Glee again in the future , depending on the right storyline . In January 2011 , Paltrow confirmed that she would be reprising the role . Murphy stated that she would appear in episodes fifteen and sixteen as a sex education teacher , and would serve as a love interest for Will , though she actually appeared in episodes fifteen and seventeen . Stamos also reprised his role as Emma 's husband Carl . As of March 2011 , he was unsure whether he would return to Glee again , but stated that he might do so to conclude Emma and Carl 's storyline , explaining : " I think people like me on there , but they really love Will and Emma together . So I don 't know how much longer people can stand Will and Emma not being together . " 
