Lil Wayne claims Drake visited him in prison and told him he was sleeping with his then-girlfriend.
According to TMZ, the 'Lollipop' hitmaker has confessed in a book proposal, a portion of which has been obtained by the gossip website, that the 28-year-old rapper paid him a visit while he was in Rikers Island jail in New York City for gun possession and made the confession.
Wayne - who served eight months of a one-year sentence in the prison from March to November 2010 - wrote: "This is the type of s**t that a man never wants to find out when he's locked up. Or, maybe so, cause only God knows what I would have done if I wasn't locked up right now."
In the proposal, Wayne - who previously signed Drake to his Young Money record label - goes on to admit hearing the news was the "worst thing" he could've ever discovered.
He is quoted as saying: "I woke up feeling f***ed up about the f***ed up day that I had ... finding out that she f***ed Drake was the absolute worst thing I could've ever found out.
"As a man, honestly, that s**t hurt ... and not because it was Drake, it could have been any man. It would've hurt the same."
The website also reports that Wayne - whose real name is Dwayne Carter - claims the woman told him she had slept with Drake the day before they met.
What's more, there is said to be "intense interest" from publishers about the 32-year-old star's book proposal.
In February last year, Wayne was a special guest during Drake's set at a basketball event, where he performed several hits.
Drake also features on a number of songs on Wayne's as-yet unreleased 11th studio album 'Tha Carter V'.