"Marvel's Agents of S.H.I.E.L.D." succeeded in its first season to prove "Not All Heroes Are Super," but cast and fans alike would still enjoy seeing some of Marvel's cinematic superheroes stop by the show to assist the mortal ones.

Cast members Clark Gregg, Ming-Na Wen and Chloe Bennet all have a specific Marvel character they would like to see make a guest appearance or cameo on "S.H.I.E.L.D."

"Chris Pratt," Bennett immediately answered at the "Agents of S.H.I.E.L.D." panel at The Paley Center of Media's annual PaleyFest NY on Oct. 19. Pratt played Peter Quill, a.k.a. Star-Lord, in this summer's blockbuster hit "Guardians of the Galaxy."

Gregg also went with a "Guardians of the Galaxy" character. He chose Groot, who was last seen as a tiny potted plant at the end of the movie. "He's even smaller. He may be cheaper," Gregg joked about getting the sentient tree who only says "I am Groot."

Wen wants to continue the theme of female empowerment in the Marvel universe that will be strengthened by the addition of Bobbi Morse, a.k.a. Mockingbird (Adrianne Palicki), in the next episode. Wen has been asked by many fans on Twitter if Melinda May and Black Widow, played by Scarlett Johansson, will team up soon.

"I think that would be really kick a**," Wen said.

The "S.H.I.E.L.D." cast mates aren't the only ones asking for some movie star power on the show. Some of the actors behind Marvel's biggest superheroes have asked to guest star on the series.

"Nothing is impossible. But there might be a fair amount of red tape involved in something like that," "Iron Man" star Robert Downey Jr. wrote in a Reddit AMA on Oct. 7. "I love Clark Gregg, and am pleased the show is doing so well."

Jeremy Renner, who plays Hawkeye in the cinematic universe, also said he would consider coming on the show if Marvel came to him with a "strong" idea.

"I love me some Clark Gregg, he's so great," Renner said during his own Reddit AMA on Oct. 18. "We killed him and brought him back to life to do 'Agents of S.H.I.E.L.D.,' he's so good!"

The movie star attention came as a "delight" for everyone who works on "S.H.I.E.L.D.," according to Jeph Loeb, the head of Marvel TV.

"It was something that made everybody who works so hard on the show feel like, 'Wow, Iron Man said we were cool,'" Loeb told Headlines & Global News exclusively.

"Even though we're a hit show and have millions of viewers, just knowing someone who is that involved in the Marvel universe and that aware of who we are and what we're doing is something that I think all the show runners and everyone in the cast and our crew who just works tirelessly, really thought was really cool."

Big screen characters including former S.H.I.E.L.D. director Nick Fury (Samuel L. Jackson), Agent Maria Hill (Cobie Smulders), and Lady Sif (Jamie Alexander) have already made guest appearances on the show to assist Gregg's character Phil Coulson and his team.

Loeb originally pitched the idea of a TV series to "The Avengers" director Joss Whedon right after that film had premiered to phenomenal box office success in 2012. They chose to develop the show around Agent Coulson, who had starred in all the Marvel movies up to that point except "Captain America: The First Avenger" and "The Incredible Hulk."

The show idea only had one problem: Whedon had killed Coulson in the middle of "The Avengers" movie.

"When we first started talking about doing the show, [Whedon] said, 'Well, we can't do the show without Coulson.' And I said, 'The problem is you killed him," Loeb said during the panel. "We talked about does the show take place five years ago... and then he just does what Joss does, this little enigmatic smile, and says, 'No, I think I know.'"

The writers carefully choose which established characters they want to include based on the story that they want to tell on the small screen.

"What we always try to do is [find] the right character. How do we best apply that character into our show and see where we go with it," Loeb said.

The biggest challenge the "S.H.I.E.L.D." writers face when trying to introduce new Marvel characters is not to conflict with characters already in development for the movies at Marvel Studios. So far, the show has successfully added Marvel comic book characters Deathlok, Carl "Crusher" Creole, a.k.a. The Absorbing Man, and Mockingbird.

The conversation around "S.H.I.E.L.D." has changed in the course of one season. Before the series began last year, the cast and crew were asked the same questions over and over: Is Iron Man going to be on the show? Is the Hulk going to be on the show? Is Captain America going to be on the show?

"S.H.I.E.L.D." now has its own committed fan base that is far more interested in the main characters of the series.

"What's really been the success of this season, and this tremendous cast and writers, is that the questions we get asked now are like, 'Who is Skye's father? What's the deal with the writing on the wall? Is Ward redeemable? Are we going to find out about the Cavalry and the backstory?'" Loeb said. "And what that means is [the fans are] invested in the show."

Loeb and the cast wouldn't divulge any other upcoming Marvel guest stars. The show does want to prove it can handle its TV characters well so they possibly can play a bigger role down the line.

"Our hope is to always be able to let all the other divisions know that we're not going to fumble the ball. We're actually hoping to be able to introduce somebody that will at some point, you know, will appear in a Marvel major motion picture. That would be the real thrill," Loeb said.