A.J. McLean says Nick Carter's wedding was ''bittersweet.''
The Backstreet Boys star, 34, married fitness expert Lauren Kitt in an ''emotional'' ceremony in Santa Barbara, California on Saturday (12.04.14), and his bandmate admits it was tough watching the youngest member of the group, who went to rehab in 2005 for alcohol addiction and previously admitted he has a ''toxic'' relationship with his family, walk down the aisle.
The 'I Want It That Way' hitmaker, 36, told PEOPLE.com: ''It was bittersweet. We're so, so proud of him. He's been through hell and back as we all have, once in our life here or there.
''And you know, we're all family. We're all brothers. To see our little baby brother finally make that big, big final step. Next step is having kids. Obviously they just got married, so obviously take your time.''
A.J., whose 17-month-old daughter, Ava, was a flower girl and walked down the aisle just days after taking her first steps, said Nick's nuptials were ''beautiful, rustic'' and ''very small.''
The groom's bandmates Brian Littrell and Howie Dorough were also on hand for the celebrations, but Kevin Richardson was not present.
Nick's younger brother Aaron Carter, 26, also missed his special day, as he claimed his flight was cancelled from Washington DC at the last minute.
Nick skipped his sister Leslie's funeral in January 2012, and later claimed his family blamed him for her drug overdose.