Christina Aguilera attended an event with her ex-husband this week.

The 'Your Body' hitmaker, who gave birth to daughter Summer Rain with fiancé Matthew Rutler last month, reunited with Jordan Bratman and her former mother-in-law for their six-year-old son Max's school picnic in Santa Monica, California.

An eyewitness told E! News: ''They seemed really cool with one another.

''[Christina] was very friendly with anyone who came up to her. She interacted with all the kids and parents. She was glowing, she looked really happy.''

The former spouses spent more than two hours together and music executive Jordan walked the blonde beauty to her limo after the event and hugged her goodbye.

Christina and Jordan split in 2010 after five years of marriage shortly after she returned from filming the movie, 'Burlesque,' on which Matthew was a production assistant.

After confirming their split, she explained: ''When I finished filming, I didn't feel right in my own shoes [at home]. I had a lot of things stirring inside of me that I felt were being suppressed. We tried to work on the marriage and figure out a common ground. But the problems were obvious.''

The 33-year-old star also admitted that their relationship was initially tense following their separation but predicted they would be friends in the future.

She said: ''For Max's sake, we keep in communication and try to be as civil as possible, but there's some pain. There's discomfort when we're together. But I know in my heart we'll find some sort of ground where we'll eventually laugh together again and be okay for Max.''