Posting a picture showing a woman (Tesla) who is upset by her boyfriend (Elon) checking out another woman (Twitter), he said, "So may seem like below, but not true."
"To be clear, I'm spending <5% (but actually) of my time on the Twitter acquisition. It ain't rocket science!" he tweeted.
"Yesterday was Giga Texas, today is Starbase. Tesla is on my mind 24/7."
Tesla this year opened its new car factory in Texas, and Musk's rocket company SpaceX has a launch site known as Starbase in Boca Chica, Texas.
Tesla shares have lost one third of their value since the billionaire disclosed his stake in Twitter in early April and sold $8.5 billion worth of Tesla stocks in a move seen to help finance his $44-billion Twitter deal.
Further hurting stocks are China lockdown measures that dampened Tesla's production and an exclusion of Tesla from a widely-followed S&P sustainability index.
Tesla bull Daniel Ives, an analyst at Wedbush, on Thursday cut the target share price of Tesla due to the China production disruption and warned of "distraction risks" from Musk's Twitter deal.
Leo KoGuan, a major individual investor in Tesla, on Thursday called on the electric carmaker to buy back shares.
"Tesla must announce immediately and buy back $5 billion of Tesla shares from its free cash flow this year and $10 billion from its free cash flow next year, without effecting its existing $18 billion cash reserves with ZERO debt," KoGuan said in a Twitter message to Tesla's head of investor relations, Martin Viecha.
Viecha was not immediately available for comment.
Last year, KoGuan, the third largest individual shareholder of Tesla, said he was investing billions in Tesla because he believes in Musk's "great mission that I share." He said in March that he was buying more Tesla shares, not selling during the stocks' dip.
(Reporting by Hyunjoo Jin; Editing by Nick Zieminski and Chris Reese)
By Hyunjoo Jin