The Tesla titan and the Oracle co-founder swapped text messages “into the easy morning hours” before he announced he was putting the $44bn purchase “temporarily on hold”, a court filing reportedly shows.
A Twitter court filing from 16 September states that Mr Musk’s phone records show he exchanged texts with Mr Ellison on 12 May and until 12.20am on 13 May, according to Insider.
That was just four hours before Mr Musk tweeted that the deal was not going ahead until he got more information about fake and bot accounts.
Mr Musk then sent a letter to the Securities Exchange Commission on 8 July notifying them that he was backing out of the purchase.
Twitter wrote to the Delaware Court of Chancery on 16 September claiming that Mr Musk’s lawyers have not provided the messages after they were subpoenaed.
Twitter also subpoenaed Mr Ellison, a former Tesla board member, in August.
The Oracle co-founder pledged $1bn to back Mr Musk’s Twitter bid and the pair are longtime friends.
Twitter and Mr Musk will go to trial in Delaware on 17 October to try and resolve the billionaire’s attempt to cancel his purchase, which has been approved by the Twitter board and the company’s shareholders.
All depositions in the case have to be complete by 29 September, with Mr Musk due to sit down for his this week.