The "Arrow" star goes live on Facebook to speak in solidarity with his cast and crew following harassment claims.
"If they need my help in any way, shape or form, they will get it," Amell said in a Facebook Live video on Monday afternoon.
With an investigation into Kreisberg still ongoing, the actor didn't mention the EP by name, but added, "If you don't know what I'm talking about, I'm sure that you can figure it out."
Amell told his Facebook followers that he spoke to the cast and crew about the issue Monday morning. "I certainly can't pontificate in an eloquent way or in such a succinct manner as Emily [Bett Rickards] did, like ["Supergirl" star Melissa Benoist] did, like Caity Lotz did. I stand behind and fully support everything that they said."
He continued, "Our biggest asset on 'Arrow' is our crew, and furthermore, their biggest strength and our biggest strength is working at it as a team. I think that we can do this because we promote and we champion a safe and progressive work environment."
"I told them this morning and I tell you now, and I meant it, that if anyone ever feels anything less than 100% safe or anyone feels as though they aren't allowed to express themselves and be the person that they are, that they should come to whoever they're supposed to go to, and I'll stand right beside them. Right behind them. I'll speak on their behalf if need be."
He ended the brief video by saying, "In situations like this, if you're not an active part of the solution, then you are part of the problem. Period."
Kreisberg, who is a co-creator and EP for shows including "Supergirl," "Arrow," "The Flash" and "DC's Legends of Tomorrow," was suspended following allegations of sexual harassment from more than a dozen CW employees. Warner Bros. is conducting an internal investigation.
"Supergirl" star Melissa Benoist spoke out forcefully on Twitter on Sunday, saying "When people are mistreated, they should have a safe forum to speak their truth and always be heard." "Arrow" stars Emily Bett Rickards and Caity Lotz also addressed the issue on social media.
To the brave women and men who are coming forward to condemn their abusers... I add my voice to the choir of support. You are the ones ushering in change that would allow all of us to work in an environment where we are respected and safe— Caity Lotz (@caitylotz) November 13, 2017