Oprah failed to recognise one of world's biggest stars at Ellen's birthday

Oprah tells Ellen about not recognising one of the world's biggest stars. Photo / Youtube

Oprah has revealed that she failed to recognise one of the most famous actors on the planet at Ellen DeGeneres's recent 60th birthday bash.

Oprah was just one of the megastars at the party with some of the other guests including Kim and Kanye, Reese Witherspoon, Jennifer Aniston, James Corden, Jennifer Lopez, Pharrell Williams and Pink.

"There were so many famous people at this party," Oprah said to Ellen on her talk show.

"When I was doing my show, famous people came on and they looked like themselves. At your party, they're all disguised."

Oprah said that during the party a guy in a baseball cap walked past her twice and said, "What's going on?" But she had no idea who it was.

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Thanks @theellenshow @oprah for this moment ❤️what a fantastic night

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Later in the evening, she was chatting to The Weeknd when the mystery guest approached her again.

"This guy comes back and I'm thinking, 'I know it's somebody, who is it? Is it Justin Timberlake? I don't think it's Justin Timberlake,'" Oprah said.

"So The Weeknd says to him, 'Hey man, I really loved that film you did.' And he says, 'No, that wasn't a good film for me, that wasn't my favourite film.'"

Oprah sensed and opportunity to figure out who the guy was and asked him, "What was your favourite film?"

"And he says, 'The Aviator.' And I go, 'Leonardo, you're so funny!'"

Yep, Oprah failed to recognise Leonardo DiCaprio.

Ellen's birthday party was quite the wild evening with comedian David Spade revealing that someone was passing around a "big rolled-up doobie" at the event.

Spade admitted that he indulged and later felt a little light-headed at the soiree.

"I see Oprah and I go, 'I should talk to Oprah,'" he recalled on Ellen's talk show.

"Then the little embers in my brain that were still alive go, 'Nope, abort, abort.'"

The former Just Shoot Me star's memories from the event are a little hazy and he told Ellen: "I thought you were Justin Bieber for the first half-hour but only because of your haircut."