Mitt Romney is meeting with Sheldon Adelson -- the billionaire casino magnate and big Newt-Gingrich supporting super-PAC donor -- in Las Vegas on Tuesday, according to CBS News and CNN. Romney is holding a fundraiser later Tuesday, hosted by Donald Trump at his hotel, that Gingrich will also attend.

Adelson and his wife, Miriam, gave $20 million to Winning Our Future, the pro-Gingrich super PAC. The cash infusion helped buoy the former GOP presidential candidate's campaign, though Gingrich's own campaign eventually ended with $4.7 million in debt.

Adelson and his wife also gave $5 million to the GOP Congressional Leadership Fund, a GOP-aligned super PAC supporting congressional candidates.

He and his family have donated some $26.5 million to super PACs, pushing Adelson past liberal billionaire financier George Soros to become the all-time leader in giving disclosed money to independent spending groups.

Adelson said to JewishJournal.com in March that he's talked to Romney "many, many times," as recently as the Nevada caucuses.

Adelson, however, has said Romney is no Gingrich, and is similar to Obama: "He's not the bold decision maker like Newt Gingrich is."

"Everything I've said to Mitt -- 'Let me look into it,'" continued Adelson. "He's like Obama. He doesn't want to put himself -- when Obama was in the Illinois Senate, 186 times he voted 'present.' Because he didn't want to establish a record for himself."

The New York Times reported in February that Adelson had relayed assurances to Romney pledging more generous support to him than Gingrich if he becomes the GOP nominee.

The super PAC supporting Romney, Restore Our Future, saw its fundraising fall in April. Adelson, who made $7 billion in 2011 and has a net worth of about $25 billion according to Forbes, could provide a crucial funding source for the group if he so chooses.