Actor Terrence Howard has blamed an attack of the nerves and a bad memory for his bungled presenting stint at the Oscars last month (Feb15), confessing he forgot his lines as he laid eyes on his The Butler co-star Oprah Winfrey and Meryl Streep in the audience.

The Iron Man star was tapped to highlight two of the Best Picture nominees, Whiplash and The Imitation Game, during the Los Angeles ceremony, but he appeared to become overwhelmed by his emotions as he took the stage, even pausing to collect his thoughts as he bizarrely gushed about the dramas.

As he introduced war film The Imitation Game, he stopped and said, "I love this next film, it's amazing. I'm blown away myself..."

Howard now reveals he had to improvise during his speech because the stubborn star wanted to prove he was one actor who didn't need a teleprompter to help deliver his lines.

Laughing about the embarrassing Oscars appearance during an interview on America's The Tonight Show Starring Jimmy Fallon on Monday (02Mar15), Howard says, "The worst part about this, is I'm like, 'I'm at the Academy Awards, I got Meryl Streep, I got all... the best actors in the world (attending), and they're up there (presenting), reading a teleprompter...' I was like, 'Man, I can do that (without help)!'

"So everybody that went up there (onstage to present), I'm clowning (poking fun at) them, telling my wife, 'Look at this, I can do better than that. Watch when I get up there.'"

But Howard's presentation didn't go to plan and he struggled to remember what he had spent hours learning as he also contended with a wardrobe issue and became starstruck by the big names watching him from the audience.

He explains, "I forgot to wear a belt that day, so I'm pulling it (his pants) up... I get out there and I'm breathing, I'm like, 'I know I got this memorised, I worked 18 hours to work this out. I'm 'bout to kill it (do really well)!'

"I get out there and there's Oprah. (I'm thinking), 'Hi Oprah! Oh, oh, read the lines, read the lines' and I try to look up and (read the lines) and I'm like, 'No, I'm not gonna read the prompter, I'm gonna say it from (the) heart', so I start off (and)... I choked!

"I thought I had it together and then I hit the microphone and I was like, 'Maybe nobody noticed!'"