The on- and off-screen couple – along with Zac Efron, Andrew Garfield (sans girlfriend Emma Stone) and Will Kopelman (sans wife Drew Barrymore) – made their way to Englewood, N.J., where Hollywood producer Kevin Turen wed Evelina Oboza on Saturday.
"They stuck to each other's side all night," an attendee tells PEOPLE of Stewart, 22, and Pattinson, 26, who partied with guests until dawn and were spotted walking hand-in-hand during the celebration.
And the bride wasn't the only one (likely) wearing something borrowed.
Before heading to the wedding, Stewart realized she forgot her dress. The solution? The Twilight actress strapped on a short, navy Zac Posen cocktail dress from the groom's sister Ashley's closet (that matched her Christian Louboutin shoes just fine).
By the end of cocktail hour, however, she was back in her own wardrobe – jeans, a black tank top and a blazer – as she mingled with fellow guests.
Although Stewart didn't show off the moves she put on display during her Twilight wedding, a date-less Efron, 24, tried his hand at the hora, a traditional Jewish dance, before hanging out with mainly male partygoers for the evening. And Pattinson got in the groove manning the deejay's laptop for a bit.
Other special guests: Harry Morton, Sarah Roemer and Tovah Feldshuh.
After spending the night at the groom's house, Stewart headed to Paris for a photo shoot and Pattinson flew back to Los Angeles. Efron kicked back by the pool Sunday until after dinner.