PRESIDENTIAL PARTY TIME

THE 84TH BIRTHDAY PARTY OF FORMER FIRST LADY BARBARA BUSH INCLUDED SEXY YOUNG PEOPLE IN SKIMPY BATHING SUITS . . . AND SOME SERENADING FROM LORENZO LAMAS!!!

Former First Lady BARBARA BUSH celebrated her 84th birthday at the family vacation home in Kennebunkport, Maine on Saturday. And it looks like the action got WILD!

Dig this: Barbara and her husband . . . the FIRST PRESIDENT BUSH . . . invited the cast of a local production of the musical "A Chorus Line" for what turned out to be a SEXY POOL PARTY!!!

(--Check out the pics of Barbara chilling with a guy in a Speedo . . . and George with a bikini babe on his lap below!!! )

The cast also included "Mega Shark vs. Giant Octopus" superstar LORENZO LAMAS . . . who serenaded Mrs. Bush with everyone's favorite Spanish-language ballad, "Solamente Una Vez"!!!

You might not recognize the title, but that song's actually been done by everyone from Julio Iglesias to Andrea Bocelli, the Three Tenors and even Bing Crosby. You can see VIDEO of Lorenzo Lamas singing it, here . . - http://www.tmz.com/videos?autoplay=true&mediaKey=76b40b04-8c2b-4a48-bcde-e70cdf5dbbe6