MICHAEL PHELPS has the gold AND the girl!

The swimming sensa­tion had a secret weapon helping him charge through the London Games to become the most decorated Olympian of all time – bombshell blonde girlfriend Megan Rossee, 25.

The 27-year-old champ, who has won more Olympic med­als than anyone in history, has kept the relationship on the down-low since he and the aspiring model started dating earlier this year.

But as these pictures show, Megan has already bonded with Michael’s protective mom, Debbie, and his close family and friends.

Megan’s father, Wayne Rossee, told The EN­QUIRER exclusively that the two met earlier this year at a Las Vegas nightclub and have been secretly dating ever since. “Michael wanted Megan to be by his side in London for the Olympics, so he flew her over there to cheer him on,” revealed Wayne, at the family’s home near Long Beach, Calif. “I think she’s helped him get his head straight for the Games.

“They are a good fit for each oth­er. She is athletic, loves sports and even played soccer in college.”

According to another source, Megan has “been a rock for Michael,” and was by his side not only during the Olympics but also during the Olympic trials in Omaha, Neb., in June.

Over the past few months, Megan has taken to Twitter to gush about her “bear.” Before she arrived in London, she tweeted that she missed him and couldn’t wait to spend time with him.

But despite the fact that he’s really flipped for the 5-foot-9 stunner, Michael warned Megan from the time they first hooked up in January that swimming would be his pri­ority until the Olympics were over.

Michael told her that he wanted to keep their romance quiet until after the Olympics,” confided the source. “Now he wants her to quit her job as a cocktail waitress in the L.A. area so she can travel the world with him after the Olympics.”

The 6-foot-4 swimming phenom has been determined that the only head­lines he made in the build-up and during The Games were about his prowess in the pool. After the Beijing Olympics in 2008, the aquatic wonder boy made news for all the wrong reasons – once for a drunk driving incident, and another time when photos surfaced of him smoking a marijuana bong. And one of his previous girlfriends, 2009 Miss USA runner-up Carrie Prejean, sparked controversy with her outspoken opposition to gay mar­riage. Then, in 2010, he was linked with another high-profile beauty, reality star Brittny Gastineau.

“Michael is done with the posers and scandal-plagued bimbos,” added the source. “He promised Megan that when the Olympics are over he’ll make her a priority. Michael thinks she’s a keeper. She’s gorgeous, smart and, best of all, his mom likes her. The fact that Debbie approves shows how serious this relationship really is. Who knows, Megan could be a future bride!”