Kris Jenner's Lavish 70th Birthday Party, Surprise Wedding?

Kris Jenner will celebrate her 70th birthday in grand style this weekend, and there's a buzz this may well be a surprise wedding!!!

Multiple sources with direct knowledge tell TMZ ... the bash will be held at the $165 million Beverly Hills estate of Jeff Bezos and Lauren Sanchez.

We're told around 300 people will attend. We're also told there will be a major recording artist performing during the party.

Now here's what's interesting ... one of our sources mentioned this is a surprise wedding and almost no one outside a close circle knows about it. We cannot confirm, but there you go. We do know virtually most -- if not all -- the guests believe it's just a birthday party.

Interestingly, we're also told cameras for "The Kardashians" reality show will NOT be present, so go figure.

As you know, Kris has been dating Corey Gamble for 11 years. It's important to note, Kris has never talked about being engaged to anyone.

Kris actually turned 70 on Wednesday. Many of her kids -- Kim, Khloe, Kylie, and Kendall -- all attended Jeff and Lauren's nuptials over the summer in Italy -- along with Kris -- so it's not surprising the couple would open their home to Kris and all her pals.