PHOTO: Newlyweds Blake Lively and Ryan Reynolds Attend Amber Tamblyn and David Cross' Wedding!

Blake Lively and Ryan Reynolds attend Amber Tamblyn and David Cross' wedding on Oct. 6.
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Less than a month after their very own nuptials, Blake Lively and Ryan Reynolds were in the "I do" spirit again — but this time they were guests at Amber Tamblyn and David Cross' wedding on Oct. 6.

"All of Amber's Sisterhood of the Traveling Pants co-stars attended her wedding," a source close to Amber tells Life & Style. "Blake, America Ferrara and Alexis Bledel were all there."

NEWS: Amber Tamblyn marries David Cross

The cast was also in attendance at Blake and Ryan's wedding in Mount Pleasant, S.C., on Sept. 9.

In a picture titled "The Reynolds #weddinginthewoods" posted by Roots drummer Questlove, who deejayed at the wedding, on Instagram, Blake and her hubby are seen smiling and conversing with other guests.

NEWS: Blake Lively and Ryan Reynold's wedding

Questlove took a bunch of photos throughout the ceremony, which included snapshots of America, actor Jason Ritter and Amy Poehler!

So how was the second Sisterhood reunion?

"The girls have stayed close from working on the movies together," the source tells Life & Style. "America and Blake actually planned Amber's bachelorette party in New Orleans. With Blake and now Amber, they have all had a lot to celebrate."