Lilo & Stitch co-director Chris Sanders has admitted that the high praise Frozen earned for its celebration of sisterhood was “frustrating,” considering his movie carried that message first.

Disney’s animated hit Lilo & Stitch was released worldwide in 2002, 11 years before Frozen debuted in 2013. Both movies explored the relationship between two sisters, prioritizing that bond over a romantic storyline, but Sanders told The New York Times that his movie, which came first, didn’t seem to receive as much recognition for that as Frozen.

“To be clear, I think ‘Frozen’s’ great,” Sanders asserted in the interview celebrating Lilo & Stitch’s 20th anniversary, per Variety. “But it was a little bit frustrating for me because people were like, ‘Finally, a nonromantic relationship with these two girls,’ and I thought, ‘We did that! That has absolutely been done before.'”

Lilo & Stitch explores the bond between a young girl and her older sister Nani through the Hawaiian concept of Ohana (family) as they grapple with an outlaw space alien that comes into their lives, while Frozen focuses on the relationship between sisters Anna and Elsa and how their love for one another can help them to overcome the challenges they face.

“When [Lilo & Stitch] came out, that’s what a lot of critics talked about,” Lilo & Stitch producer Clark Spender added, referring to the animated movie’s nuanced depictions of family relationships. “Those moments that were based in reality in a way that people could see themselves in, and it didn’t feel like they were cartoon characters.”

When Lilo & Stitch was released in 2002, it grossed $237 million at the box office on a budget of $80 million. Its success led to video games, sequels, spinoffs, and an animated series. The Disney film is also said to be getting the live-action adaptation treatment, though not much has been said on that since reports circulated that John M. Chu was in talks to direct.

Frozen hit theaters in 2013 and received praise for subverting expectations and telling a much more modern type of Disney story. The movie broke box office records for an animated movie and crossed over the $1 billion mark at the worldwide box office. Frozen has since become a franchise of its own, with animated shorts, featurettes, and a feature-length sequel.

Adele Ankers-Range is a freelance writer for IGN. Follow her on Twitter.