Natalie Portman and Benjamin Millepied Take Son Out for a Concert Night

By Evan Lambert

08/09/2012 at 04:00 PM EDT

While many couples opt for lavish, tropical honeymoons, Natalie Portman and new hubby Benjamin Millepied have decided to keep things low-key.

The two were spotted enjoying an LA Philharmonic concert with 1-year-old son Aleph on Tuesday night.

"[Natalie] looked pretty chilled-out," says one source. "She was wearing jeans and a T-shirt, her hair was down. ... She looked more concerned about keeping [Aleph] quiet and not disturbing anyone, than anything."

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Portman and Millepied had stepped away from their seats in the Hollywood Bowl to calm Aleph, who had been fussing – but that didn't stop them from enjoying the concert.

"[Benjamin] was really into the music," says the source of Portman's choreographer beau. He was swaying back and forth while walking with Aleph, and keeping time with the music."

Portman and Millepied, who met on the set of Black Swan in 2009, were married Saturday. The Oscar-winner had been engaged to Millepied since December 2010, and gave birth to son Aleph in June 2011.

• With reporting by SHAKTHI JOTHIANANDAN