Justin Theroux motorcycle jacket helmet boots jennifer aniston sunset blvd west hollywood Chateau Marmont

Justin Theroux enjoyed a solo ride down Sunset Blvd. without girlfriend Jennifer Aniston after leaving Chateau Marmont.

Theroux, 40, has been hanging out with Jen non-stop over the past few weeks ... most recently accompanying her to a doctor's appointment in Santa Monica.

The sexy actor, sporting a unique black and white helmet, definitely has his own sense of style. Perhaps Jen will eventually prep him up!

Even though the couple have been together for just over 3 months, could the rumors be true that the 42-year-old Friends star is desperate to become a mom? If so, enjoy those solo motorcycle rides now Justin ... because soon, your free time won't be so free.