Kelly bonds with John Diggle in sneak peek at Azie Tesfai's Supergirl episode

After visiting Central City, Gotham City, and Smallville, Arrow's John Diggle (and his portrayer, David Ramsey) has reached the last stop on his Arrowverse tour: Supergirl's National City.

EW is debuting an exclusive clip from Tuesday's episode, "Blind Spots," which addresses racial inequality and was directed by Ramsey and co-written by series star Azie Tesfai and producer J. Holtham. Following the horrific implosion of the Ormfell building, Kelly (Tesfai) springs into action to help injured members of the community. Unfortunately, she's basically doing it all on her own because Supergirl (Melissa Benoist) and the rest of the Super Friends are focused on finding Nyxly (Peta Sergeant). Thankfully, Kelly receives some assistance from one Diggle, courtesy of her brother James, and the above sneak peek reveals the moment Diggle arrives in National City to lend a hand.

"That was my most favorite scene because it was just the two of us in the apartment, and it felt like we were doing an independent film," Tesfai told EW in a recent interview on Instagram Live with Ramsey. "Because Ramsey's directing and runs behind the monitor, sets up the shot, and then comes and does his line. If we had any issues with lines, we talk it through and decide what we want to do with J. It felt so small, because between the two of us and J. we were covering kind of everything. So that was very cool. It felt very intimate in that way."

Bettina Strauss /The CW David Ramsey, Azie Tesfai, and Melissa Benoist on 'Supergirl'

She continued: "I told Ramsey this, I don't know if he remembers, but I met him my first year at upfronts, and he came up to me and was like, 'Here's my phone number. If you need absolutely anything, I've got your back, I'm here for you.' And I didn't take him up on that, which I regret, but before even knowing me, just being in this Arrowverse, he was like, 'I've got your back.' And I feel like there's a similarity with Diggle coming in with Kelly and being like, 'I see you and I got you, and I'm here for you.'"

As previously reported, "Blind Spots" will culminate with Kelly suiting up as the shield-wielding Guardian, a development that's been in the making since Tesfai joined the show in season 4. That said, Tesfai wasn't prepared for how she would feel when she put on the suit for the first time.

"It was very emotional, which was really surprising to me. I think you immediately stand up a little taller," she said. "We also had a handful of young Black kids in our episode, and to see them respond to the suit, I think, was the coolest part."

The CW Azie Tesfai 'Supergirl'

Tesfai promises that the episode will have an effect on Kelly and Alex's (Chyler Leigh) relationship moving forward.

"My favorite — and I don't want to speak for Ramsey, but I feel like it's probably one of his favorites too — is the last scene of the episode between Alex and Kelly," Tesfai said. "We don't resolve everything in the way that you can't, but we do open a can of worms and a conversation and hopefully create some healthy conversations for people to look at between two intimate partners in an interracial relationship. It's something that comes up till the [series] finale. It brings them closer together, but it's an ongoing conversation. It ends up being the first step in them really looking at what their future looks like in a real permanent way."

"Blind Spots" also marks the end of Ramsey's Arrowverse appearances this season, though the actor — who is currently directing Superman & Lois — assures this isn't the last time we've seen Diggle. And there's more to come regarding the mystery of the green box he found in the Arrow series finale.

"We just have a moment at the end where we touch on it one more time. This isn't over," Ramsey said. "I think what was important about this and smart from the writers was to tell this story of someone like Diggle, who is such a mentor and such homegrown hero, if you will, that whatever the invitation [in the glowing green box] was — if we remember the story behind Diggle, he had just gotten his wife back, just got Sara back, who disappeared from Flashpoint — that it made sense for him not to accept it immediately, and we wanted to tell that story. This is the last piece of that story. You will see Diggle again after Supergirl, and when you do, we will continue that storytelling."

Tesfai added: "That was very generous of you, because I know all of what you have planned."

Watch the exclusive sneak peek at "Blind Spots" above. Supergirl airs Tuesdays at 9 p.m. ET/PT on the CW.

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