During CBS' upfront presentation last month, the network not only unveiled the first Star Trek Discovery trailer, but they also announced that the first season will be expanded to 15 episodes, debuting this fall, followed by a weekly after-show dubbed Talking Trek. This series had more than its fair share of setbacks, with the series being delayed a number of times, largely due to the departure of original showrunner Bryan Fuller. While promoting his new movie The Mummy, in theaters starting today, producer Alex Kurtzman shed some light on the Star Trek Discovery delays, while also teasing some celebrity cameos that will pop up this season.

Collider got to speak with Alex Kurtzman, who confirmed that they are currently shooting the fifth episode of the 15-episode first season. While he wouldn't get into specifics, the writer-producer teased that there were several actors who reached out about being in an episode, simply because they're huge fans of the Star Trek franchise. While he would't name any names, the producer teased that there could be several celebrity cameos in the first season.

"So many actors are fans. We literally got a list of them that were like, 'Here are people who said they want to be on Star Trek'. It was awesome... To just be in an episode or come in or out."

Bryan Fuller had initially come aboard to serve as showrunner and executive producer, which excited many fans since he started his career as staff writer on Star Trek: Deep Space Nine and Star Trek: Voyager, before creating his own shows like Wonderfalls, Dead Like Me and Pushing Daisies. The producer had to back out of his duties as showrunner, since he was also working on Starz's American Gods at the time. Here's what Alex Kurtzman had to say about why Bryan Fuller parted ways with Star Trek Discovery, while making it clear that there are still his "footprints" on the show.

"No absolutely there are footprints left on the show. Someone once described Bryan to me as a unicorn and that's just the truth. He's a one of a kind writer. He's just unbelievably brilliant and I really, really loved working with him and I loved seeing the way that his mind worked. Bryan was very involved in American Gods and I think that the scope and scale of what Trek has become made it so that Bryan elected to say, 'I don't wanna short-change either of these two things,' they're both sort of beloved to him, so we sat down and we figured out how are we going to take what we can have of you and continue that through not only this season of Trek but hopefully set up things that are coming next season. So much of what's there in terms of story and certainly in terms of set-up, character, big ideas, the big movement of the season, that's all stuff that Bryan and I talked about."

When this new Star Trek TV series was first announced in November 2015, the original plan was to debut the first episode on CBS, before the show moved over to the network's new streaming service, CBS All Access. The show was then pushed to Summer 2017 and then to fall 2017, which is when it is currently slated to debut. When asked about the delays, Alex Kurtzman revealed that the release kept getting pushed because they wanted to make sure this series was perfect.

"We postponed our schedule because the truth is we did not want to put out something that was subpar, and as the vision expanded we started feeling like we weren't gonna be able to deliver the scope and the scale that was on the page. And CBS was extremely supportive in saying, 'Okay you know what, this is streaming, it's not like we have to beat out right away, let's do the best version of this, Trek is too important for all of us.'"

The Star Trek franchise has always been among the most forward-thinking, a tradition that continues in Star Trek Discovery. Anthony Rapp will portray the franchise's first openly-gay character, Lt. Stamets, an astromycologist, fungus expert, and Starfleet Science Officer aboard the Discovery. Alex Kurtzman also revealed that this kind of diversity will continue to be prevalent as the show continues.

"I don't feel that-going back to what you said about where television is at right now, it would be foolish of us to not only ignore it but not to take advantage of the fact that that's how people are consuming stories and they're hungrier for more complicated stories. What would have been a taboo subject 10, 15 years ago is now everywhere, and that's a beautiful thing."

No specific premiere date has been given for Star Trek Discovery at this time, but it will still debut on CBS this fall, before switching over to the CBS All Access streaming service. With a third of the production already complete, it's possible that the first trailer may be unveiled at Comic-Con 2017 next month, but that hasn't been confirmed. Hopefully we'll have more on Star Trek Discovery sooner rather than later.