Arnold Schwarzenegger and Maria Shriver again showed they can put their divorce difficulties aside when it comes to their kids, and came together for daughter Katherine's graduation from USC on Friday.

They were joined by other children -- Patrick, Christopher and Christina -- in the front row for the ceremony

She says she has always been closer to her mom, but her parent’s breakup still hurt.

Katherine Schwarzenegger, 21, the oldest child of Maria Shriver and Arnold Schwarzenegger, broke her silence on her parents recent very public split and admitted how difficult the situation can be. 

“I really do believe everything happens for a reason," Katherine told Harper’s Bazaar magazine in a revealing new interview.

Like her younger brother Patrick, Katherine Schwarzenegger has been tweeting about her parents bust-up, but her message Sunday was especially compelling.

PHOTOS: Arnold Schwarzenegger & Maria Shriver Through The Years

"Sometimes we forgive people cause we want them back in our lives," Katherine retweeted Sunday, picking up on a line one of her Followers sent her.

An author and volunteer advocate, Katherine has always been extremely close to both to both her father Arnold and mom Maria Shriver, and she's taken the high road with her tweets.

"Holding grudges is bad for your health," she wrote last Thursday.  "Forgive and let go."

PHOTOS: Maria Shriver And Kids Have Lunch

RELATED STORIES:

Arnold Schwarzenegger 'Not Willing To Commit' To Any Movies

Arnold Confessed After Maria Confronted Housekeeper About Love Child

PHOTOS: Move Over Arnold, Other Celebs Involved In Baby Scandals!

What a show of Shriver solidarity.

FIRST PHOTOS: Maria Shriver And Kids Have Lunch

Maria Shriver has held her head high as the news that her husband Arnold Schwarzengger has admitted that he fathered a child with the family maid, and she ventured out in public with her children Wednesday and RadarOnline.com has the photos for you.

PHOTOS:  Arnold & Maria Through The Years

The calm before the storm?

PHOTOS: Arnold & Daughter Grab Coffee

Arnold Schwarzenegger and his oldest daughter Katherine looked noticably glum Monday -- only a day before news broke that Arnold had fathered a child out-of-wedlock.