#Deric Augustine channels Cassius Clay in ‘Godfather of Harlem’

“Godfather of Harlem” takes an historic turn in Sunday’s episode — as Cassius Clay starts his journey to become Muhammad Ali.

Clay has beaten Sonny Liston for the heavyweight crown and is has been courted by Malcolm X (Nigel Thatch), on suspension from the Nation of Islam and looking for a way to get back into the good graces of leader Elijah Muhammad (Clifton Davis). He’s hoping that introducing Clay, a recent convert to Islam, to Muhammad will do the trick.

Actor Deric Augustine, 31, has portrayed Clay over the past two seasons of the series, starring Forest Whitaker as ’60s-era Harlem gangster Elwood “Bumpy” Johnson, Vincent D’Onofrio as Vincent “The Chin” Gigante and Giancarlo Esposito as Adam Clayton Powell Jr.

Augustine (“Saints & Sinners,” “Cloak & Dagger”) spoke to The Post about his on-screen alter-ego and about Sunday’s episode (9 p.m. on Epix).

Is there a lot of pressure to portray a world-famous icon?

I was very concerned with [Clay’s] mannerisms, his voice, his speech patterns; he had a lot of charisma, and to have that on my shoulders was really stressful. You can put your own spin on it, but you’re playing a real-life character and need it to be realistic — and not come off like you’re trying to put on a show. As soon as I got the role I started watching videos of him, interviews … I read numerous articles and I contacted my speech coach in New York and we worked on his speech, his dialect, how he delivered his words — and that’s how I conquered his voice.

I didn’t know that Malcolm X had renamed Clay as Cassius X before it was changed by Elijah Muhammad.

I knew [Clay] had a significant, brotherly relationship with Malcolm X, who wasn’t supposed to do that. We brush on that in Sunday’s episode, and I think it’s very insightful and informative for viewers. I love how this show touches so many other bases … not just about Bumpy, but about how he has these relationships with public figures. A black man in the ’60s and ’70s was not going to be well-known for graduating at the top of his class or as the world’s greatest neurosurgeon, so when Clay became the heavyweight champ he was more of a public figure and could really leverage his relationships to do what he wanted to do.

Did you do anything special to prepare for playing Cassius Clay?

Once I learned that I booked the role, I trained for two months, gained 15 pounds — I was intaking 6,000 calories a day — and was tanning twice a week, since [Clay] was a shade darker than me and I wanted to look the part. My hair is naturally curly, so I picked it out, washed it, picked it out … and they blow-dried it in hair and makeup, which is pretty much all I needed. When you gain weight it makes you look older.

Is this your first time playing an historical figure?

It is to this degree. I did a movie years ago called “Surviving Compton” and I played DJ Yella from NWA. That’s why I was so nervous, as a young actor, when I found out I was working with Forest Whitaker and Vincent D’Onofrio … it forces you to bring your “A” game and make sure you arrive on the set prepared, and that’s what I did. Working with Vincent was like being in a master class. There’s a scene in Season 1 when Chin’s people kidnap [Clay] and tie him up in a chair. I wasn’t struggling with it, but it was the first scene I did [on the series]. Vincent said to me, “When I’m telling [Clay] that the FBI is going to get a tape and that he’ll never be a Muslim, picture me telling you that I’m going to take your acting career away.” That got me instantly into the scene.