The incoming president was also at the party, as was his wife Melania, Tesla billionaire Elon Musk, and Trump Jr.'s brother Eric and sister Tiffany and their spouses.
Just last week, Anderson attended Trump's famous Christmas party at Mar-a-Lago - and once again left people buzzing with her tight red dress. Photos from the party confirmed Trump Jr. sat next to Anderson, a few seats away from Trump, Melania, and their 18-year-old son Barron.
Trump Jr. and Anderson were first spotted together on a brunch date in August - even though he was said to be engaged at the time to former Fox News anchor Kimberly Guilfoyle.
As rumors of their potential relationship spread, Trump stepped in and announced he was sending Guilfoyle to Greece as the country's newest ambassador.