Darren Criss, the resident heartthrob from 'Glee,' guest mentored on tonight's (July 31) episode of 'The Glee Project.' The theme of the ep was "romanticality," and with Criss serving as one-half of the show's gay supercouple, playing Blaine to Chris Colfer's Kurt (aka "Klaine") he was the perfect person to bring a little love to the spinoff show. He was able to impart some nuggets of wisdom to the remaining hopefuls.

Criss has done some of the most groundbreaking romantic scenes on the show, so he told the contestants that being believable is both critical and crucial. "Romance is inherently [about] being vulnerable and having a sincere and unique connection because of that," Criss said. So for the homework assignment, which paired couples up for Extreme's ballad 'More Than Words,' Criss wanted them to demonstrate chemistry, since relationships are the cornerstone of 'Glee.'

Criss felt that Ali and Blake were tender and earnest in their performance, looking like a couple in love as they nuzzled. Criss felt that Blake, the favorite to win the season, nailed it, and chose him as the homework assignment winner. It was Blake's first win and he was able to choose which partner he wanted for the music video. He elected to work with Ali again since their chemistry felt real and natural.

It was a heartthrob-to-heartthrob mentoring sesh, that's for sure. Criss told Blake that the feeling is being in love and to show it. He said he wants to see it, and if thinking of his girlfriend makes him feel "love" and takes him to that place, then he should channel that into his performance.