The breach was possible due to a bug in the software of the photo and video sharing app.
The Facebook owned social network admits a bug in its software caused the breach, which had the email addresses and phone numbers of these celebrities exposed.
“Its application programming interface (API) was at fault,” it said - but added that the bug had since been fixed.
Instagram said however that passwords had not been stolen but warned users to watch for suspicious activity on their accounts.
The photo sharing app did not say which accounts had been affected. It went on to warn its verified users to "be extra vigilant" about unexpected phone calls, texts, and emails.