NO! BRITNEY SPEARS IS NOT ENGAGED & SHE HAS NOT BEEN ABDUCTED BY ALIENS! LOL!

Britney Spears' dating life - like her tour - has turned into one giant "Circus."

Last month, we reported that the pop star was bumping and grinding with a tour backup dancer named Geo while her daddy was taking care of business in L.A. Reports then surfaced that Brit is making sweet music with yet another backup dancer, 21-year-old Chase Benz.

Now a whole 'nother case of crazy is coming out: An employee of land developer John Sundahl is claiming Brit and Sundahl are going to tie the knot!

According to The National Enquirer, Sundahl, a 40-year-old real estate whiz kid, met the pop princess in rehab in 2007 during Britney's bald days - and has held a torch for her ever since.

The multimillionaire's personal pilot, who referred to himself as "Lance Chase," told us: "Britney and John used to date, but they reconnected after her show in New Jersey, and now they're engaged. He got down on one knee in a Subway sandwich shop in Santa Monica a week ago and proposed with a $4.5 million marquise-cut diamond that he bought at a Frankfurt jewelry store."

Chase continued crazily, "They plan on getting married at his aunt's farm in Germany in six weeks. It's very hush-hush, even to the employees. He's even putting a $350K fence around the property."

We caught up with Sundahl - who's so wealthy that he's currently staying at his parents' house in Woodland Hills, Calif. - and got his side of the "story."

"I don't want to talk about that," he said, before changing his tune and spilling some details about his "relationship" with the singer. "Britney doesn't want to do anything until the tour is over. She wants press for her tour and not for an engagement," he dished subtly.

A representative for Spears said: "Britney is not engaged, she did not get proposed to at Subway last week - she is currently on tour - she is not getting married on a farm in Germany, she did not receive a $4.5 million marquise-cut diamond ring. Oh, and she has not been abducted by aliens either."

There you have it: ringside seats to Britney's own personal circus.