Jennifer Lopez, Oprah Winfrey and Katie Holmes Lead Today’s Star Sightings

From Harvard to London, Hollywood’s finest have been keeping busy — and looking fabulous.

Oprah Winfrey donned a cap and gown on Thursday as she took to the stage at Harvard University in Cambridge, Mass. The television queen received an honorary Doctor of Laws and later gave a commencement speech to the Class of 2013.

“Oh my goodness. I’m at HAAAARVARD! Not too many girls from rural Mississippi have made it all the way here to Cambridge . . . I consider today to be a defining milestone,” Winfrey said in her speech. [via USA Today]

Elsewhere on the east coast, Katie Holmes got into character on the set of her new film Mania Days, Sarah Jessica Parker accompanied her adorable daughters Tabitha and Marion to school while Vinny Guadagnino hit the After Earth after party at the Standard Hotel.

Across the pond, Prince Harry suited up for the Walking With the Wounded Crystal Ball Gala Dinner in London, Jennifer Lopez paid a visit to the BBC Radio 1 studio while a pregnant Jenna Dewan bundled up as she ran errands around town.