Elon Musk, co-founder and CEO of Tesla Inc, speaks during a news conference in Tokyo on 8 September 2014. (Yuriko Nakao/Bloomberg)

Tesla Inc founder Elon Musk is working with US firms Wachtell, Lipton, Rosen & Katz and Munger, Tolles & Olson to move forward his proposal to take the electric carmaker private, while Tesla's board of directors has retained Wilson Sonsini Goodrich & Rosati and Latham & Watkins to evaluate the chief executive's bid.

After facing a series of questions over possible funding sources for such an effort, Musk has signalled that he remains serious about pursuing the potential buyout, announcing via a Monday evening tweet that he is working with financial advisers from The Goldman Sachs Group Inc and private equity firm Silver Lake Partners, with Wachtell and Munger Tolles serving as outside legal advisers on the proposal.

Wachtell corporate partners David Karp and Ronald Chen in New York led a team from the firm that counselled Musk and Tesla two years ago on the Palo Alto-based company's merger with SolarCity Corp, another entity that Musk already controlled. (Karp and Chen also just advised Arlo Technologies Inc, a smart-security spinoff from Netgear Inc, on a $163m (£128m) initial public offering earlier this month that generated $5m (£3.9m) in legal fees and expenses for Wachtell, according to securities filings.)

Monday's announcement appears to be the latest effort by Musk to convince investors, as well as the US Securities and Exchange Commission (SEC), that he is keen on his $72bn (£56bn) plan to take Tesla private. Musk tweeted last week about having "funding secured" for a possible buyout, which has triggered investor suits and an investigation by the SEC into the accuracy of his public statements.

Tesla's board, which said it hasn't yet received a formal going-private proposal from Musk, said in a securities filing Tuesday that it has created a special committee to evaluate any offer from its CEO. Three independent directors – Brad Buss, Robyn Denholm and Linda Johnson Rice – are being advised by Latham and will retain an independent financial adviser once the board receives an official proposal.

Wilson Sonsini, a firm that enjoyed a long relationship with Tesla and other Musk-related entities, is advising the company's board itself.

Musk claimed that he had been approached several times during the past two years by Saudi Arabia's sovereign wealth fund about support to take Tesla private, which is why he wrote "funding secured" in the tweet last week.

"Going back almost two years, the Saudi Arabian sovereign wealth fund has approached me multiple times about taking Tesla private," Musk wrote. "Recently, after the Saudi fund bought almost 5% of Tesla stock through the public markets, they reached out to ask for another meeting. That meeting took place on 31 July … I left the 31 July meeting with no question that a deal with the Saudi sovereign fund could be closed."

Musk said he is also seeking additional outside investors. Meanwhile, any detailed proposal would be presented to the special committee of Tesla's board for final evaluation, he added.

In an odd twist, on Monday the rapper Azealia Banks, who claims to have been invited to Musk's home over the weekend along with the musician known as Grimes, said that Tesla's CEO was "scrounging for investors to cover his ass after that tweet".

Musk, through Tesla, said he had never met Banks and called her claims "complete nonsense".