From PEOPLE Magazine Click to enlarge
Last summer Chelsea Clinton and boyfriend Marc Mezvinsky couldn't convince people that they were not secretly getting married on Martha's Vineyard. Through friends and reps, they tried in vain to get the word out: They were not even engaged, much less eloping.

So when they finally had good news to tell, they knew just what to do: They sent a mass e-mail. "We ... wanted to ... share that we are engaged!" the couple wrote to loved ones Nov. 27. "We didn't get married this past summer despite the stories to the contrary, but we are looking toward next summer and hope you all will be there to celebrate with us."

No one could be happier about the news than the father of the bride, former President Bill Clinton. "Bill adores Marc," says a source who knows both families. "This is the son he didn't have."

Childhood friends who began dating in 2005 and now live together in Manhattan, Marc, 31, an investment banker, and Chelsea, 29, who is pursuing a master's degree in public health, have lots in common. Both have two parents in politics (his dad is former Iowa Rep. Ed Mezvinsky; mom is former Pennsylvania Rep. Marjorie Margolies) and both have seen their fathers weather public scandals (his served five years for defrauding investors). "They had that connection," says the source. "When not-such-great things were happening in her life, he was the protector." Says another friend: "Marc is incredibly supportive, but he's not a doormat. He's her equal in every way; he's just less well-known."

One more thing they share? The ability to keep a secret. Says one source: "I think they've known for a year that they were going to get married."