Speaking with Australia's Herald Sun, Cameron revealed that he was quite against del Toro taking the reigns on The Lord of the Rings prequel films, specifically because of Peter Jackson.
"I was telling him for a long time to get out of that thing because there is only room for one captain on the ship," Cameron says. "Instinctively I knew that Peter was going to take over and do the movie.
"Guillermo, to his credit, didn't listen to me and wanted to do continue and had some great designs -- and I have seen all the designs.
"Of course he would have done a spectacular job, but don't we want to see Peter do it? He should do it and Guillermo should do his thing.
"That's what I told both of them -- you should just stay in your corners."
Good advice! Though, to be fair, Cameron did have a horse in this race: After dropping out of The Hobbit, del Toro became available to direct At the Mountains of Madness... for executive producer James Cameron.
ยท James Cameron Mines More of Rich Pandora [Herald Sun]