The UFC did not disappoint with the first-ever sporting event at The Sphere in Vegas ... and Jeff Bezos's fiancée, Lauren Sanchez, was right there chronicling the whole amazing night.
Lots of celebs hit up UFC 306, including Chris Brown, Taylor Lewan, Andrew Shulz, Bob Iger and Shannon Sharpe.
Of course, Jeff and Lauren sat cage-side -- seats were SUPER expensive, but they scraped up enough dough -- as she pulled out her cell phone and sprayed the venue with video for her followers.