Justin Bieber is such a gentleman!

Not only did the pop star buy an $8.5M mansion for him and his wife to live in, he picked up a couple bouquets of flowers for wife Hailey Baldwin Sunday to put in the new home!

Justin and Hailey were previously staying in Justin's luxury penthouse residence at the Montage Laguna Beach for weeks while he received treatment at "brain heath center" the Amen Clinic and while they looked for a home up in LA. Well they found it and now they're back to living in the city and while Hailey seems to love it -- she can meet up with friends like Kendall Jenner at Pilates and for dinners at Nobu Malibu, and go shopping at local favorites like Fred Segal -- Justin, meanwhile, has been nesting. He's accepting deliveries at the house, getting their furnishings in order and staying home.

But why, when we spotted Hailey with pup Oscar Bieber outside the house yesterday, did she appear to be crying? Are those tears of joy over her first marital home?