Jayden Federline Spotted as Mom Britney Spears Gets Substance Abuse Treatment

Britney Spears' youngest son, Jayden Federline, was snapped in L.A. today while his mom gets treated in rehab ... and we have a pic!

Check out the photo ... Jayden palms a smoothie in his right hand as he's wearing a white tank top and floral-themed shorts.

As we told you ... sources with direct knowledge told us Britney voluntarily checked herself into rehab for substance abuse after her DUI arrest last month.

Britney has had issues with drugs -- particularly Adderall -- and alcohol for years. Part of the reason she's gone to rehab is because she knows it will look good in front of the judge, a source told us.

This is not Britney's first time getting treatment. Back in the day, the pop icon had several stints in rehab ... but always left before long.