Please welcome former President Obama to The CW's Arrowverse. The upcoming episode of Legends of Tomorrow is set to bring the former President of the United States (or in this case, future President) into the DC fold, which is something that we've known was going to happen for a while. But now we have our first look at the young Obama in the episode, thanks to a newly released promo. Not only do we get to see Obama here, but it's also revealed that Gorilla Grodd will once again be the one causing problems for The CW's DC heroes.

Legends of Tomorrow, being a DC show about heroes traversing time to fix big problems, has allowed them to bring in some pretty interesting characters during its run. The series has featured a take on Elvis Presley previously and now, we get the 44th President, Barack Obama, during his college days. The episode, appropriately titled Guest Starring John Noble, also features Lord of the Rings star John Noble playing himself. So there's a lot going on here and it seems like a must-see for fans of the DC universe on the small screen.

Guest Starring John Noble sees the heroes dealing with the barely stable timeline. As a result, the Legends must tackle two anachronisms at the same time to try and keep Mallus at bay. Sara (Caity Lotz) and Rip (Arthur Darvill) team up to stop Grodd (David Sobolov) from going after a particular target (Obama), leaving Nate (Nick Zano) and Wally (Keiynan Lonsdale) to stop Amaya (Maisie Richardson-Sellers) from changing her future. Meanwhile, the Legends think they have found a way to destroy Mallus, but they will have to create an uneasy alliance with one of their enemies.

Related: Constantine Will Be a Series Regular in Legends of Tomorrow Season 4

This serves as the penultimate episode of Legends of Tomorrow season 3, ahead of the finale on April 9. The CW has yet to announce a renewal of the series for season 4, but it's likely that's going to happen in the not-too-distant future. However, on the off chance that, for whatever reason, the network decides that they can get by with the rest of the DC Comics slate, fans need might want to prepare themselves for the possibility that these next two episodes will be the series finale of Legends of Tomorrow, as opposed to just a season finale. In either case, this upcoming episode is going to be crucial.

Assuming Legends of Tomorrow season 4 does happen, Matt Ryan will board the cast as a series regular, meaning that we're going to see Constantine pop up rather frequently. In addition to a young Obama and John Noble, this episode also features the likes of Brandon Routh, Dominic Purcell and Tala Ashe. Ralph Hemecker directed Guest Starring John Noble, which was written by Keto Shimizu and James Eagan. The episode is set to air on Monday, April 2, on The CW. Be sure to check out the new Legends of Tomorrow trailer, courtesy of the TV Promos YouTube channel, for yourself below.