"There’s a lot about the character that we want to keep under wraps I guess, and for a certain period of time. But the good part is, he’s no letdown," he told the film site. "He has a great, adventurous spirit that he shares with his son. And you know, the idea of being able to find someone that you’ve wanted to see for a long time, and I think the whole thing basically being seen through Peter Quill’s eyes, we can all understand how you’d want to meet your dad."
He added that like most kids, Pratt's Star Lord has put his father on a pedestal.
"But to finally have the opportunity to meet that person, and then begin to compare who they had in mind and what they’re really getting is a lot of what we’re doing," he said.
The 66-year-old star said Pratt is "just a sweet guy and is just a great, great sweet guy, and James [Gunn, the director] is just a load of fun and really, really knows what he wants to do."
"I was talking with Chris the other day, and I was saying, 'You know, the really fun part about this is that you and I really get to work together on this movie,'" he added. "We really work a lot together and we did many different scenes together. And that gives you the opportunity to play them many different ways."
He couldn't say much more, but he did reveal that another new character Mantis, played by Pom Klementieff, is an important player in the film.
Russell's interview may have been timed to Marvel Studios' release of an extended peek at the film.
The ad, set to David Bowie's "Suffragette City," gives fans a tantalizing few extra seconds of the movie, tying together parts of scenes shown in earlier coming attractions.
One shot in the teaser shows Pratt piloting his ship through a firefight, with his passengers -- including Baby Groot and Karen Gillan's cybernetic Nebula -- hanging on for dear life.
Another shows Rocket trying to talk his way out of a sticky situation where dozens of space pirates have their guns drawn on him and Michael Rooker's Yondu.
The new spot also shows, for the first time, Elizabeth Debicki's villainess Ayesha.
"Guardians Vol. 2" will be released by Marvel Studios, which like ABC News, is owned by Disney.