'90210' Star Trevor Donovan -- Parties with 2 U.S. Presidents, 1 Dalai Lama

What does Bill Clinton, the Dalai Lama and lonely teenage girls across the world all have in common?? They all LOVE "90210" hunk Trevor Donovan!!

The 33-year-old heartthrob glad-handed some of the most powerful people on the planet last week at the 12th World Summit of Nobel Peace Laureates in Chicago ... and TMZ has the pics.

Among the high profile guests -- Jimmy Carter, former President of Poland Lech Walesa, a couple of Kennedys, Rahm Emmanual and Sean Penn.

So why was Donovan there? Trevor recently told TMZ he's tight with the Kennedy family and has become very active in the political scene as a result. Plus, he's really, really good looking.