The Lord of the Rings star reportedly became embroiled in an altercation with Bieber while enjoying a night out with pals in Ibiza.
But when quizzed about the reasons for the fight on Australian radio show Kyle & Jackie O, the British actor was remaining firmly tight-lipped.
After laughing, the star said: "I tell you what that is, that is old news, that is such old news. What is there to say really? There is nothing to say. It's old news."
Fair enough! Keeping a dignified silence!
Plenty of rumours began swirling after the fight, mostly claiming the altercation broke out after Justin made a comment about Orlando's ex-wife Miranda Kerr.
This was never confirmed but Justin did Instagram - and then swiftly delete - a picture of Miranda. Justin and Miranda met at the 2012 Victoria's Secret Show.
But, row with Bieber aside, Orlando said he'd enjoyed his time in Ibiza.
"I hadn't been over to Ibiza in years. I had a bunch of mates text me saying, 'Come on, have a laugh, it's fun!' So I went and had a great holiday. It was amazing."
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