After being formed on The X Factor four years ago, 1D have gone on to become the world's biggest boyband.
And according to Olly, the boys' success is something that he thinks "will never happen again".
Speaking to MTV News, the 'Wrapped Up' singer claimed it would be very difficult to match what 1D has achieved since breaking out in the industry.
"There's always going to be other artists who are successful and massive," Olly explained. "But it's going to be very hard for anyone from The X Factor to be as big and successful as those boys."
Admitting the same was suggested about Leona Lewis and her impressive career, 30-year-old Olly said it could happen, but the chances are slim.
He added: "You never know. After Leona Lewis, I almost felt that was never going to happen again because she was so massive in America...
"But then One Direction came along and completely took it to another level - what they're achieving and what they're doing is ridiculous."
Olly's comments come after the 1D boys have added more gongs to their ever-growing list of accolades.
Earlier this week, One Direction were spotted arriving in Sydney and last night their trip to Oz was made even better as they took home the award for Best International Artist for the second year running at the ARIA Awards.
As well as their recent win, our favourite five piece enjoyed even more success earlier this month as One Direction took home not one, but three awards at both this year's MTV EMAs and the American Music Awards.
Just add that to their four Brit Awards, four VMAs, three chart-topping albums and nine top ten singles...
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Watch One Direction's video for 'Night Changes' here: