The newly-reunited couple appeared ''smitten'' with one another at the session at City Church in Los Angeles, where they sat quietly with friends and listened to a sermon from Pastor Judah Smith.
A source told Us Weekly: ''They were very lovey dovey and cute. They came and left together with a few friends
''They sat next to each other and listened to the sermon and were smitten with each other.''
And it seems the sessions have been having a positive effect on Justin, following months of controversial antics.
The source added: ''He looks so happy and at peace.''
The 20-year-old singer won back the 'Come and Get It' star - who he has had an on/off romance with since 2010 - after vowing to curb his wild ways and even change his friendship group.
A source told The Sun newspaper: ''He told her he can't live without her and that he's reformed his bad boy ways for good.
''He's ditched a few of the troublesome characters he's been hanging out with after advice from his management.
''And Selena thinks he's being genuine and given Justin another chance.
And as a symbol of his new direction, Justin presented Selena with a £6,000 Segway at his Beverly Hills home so they can have ''good, clean fun'' together.
The source added: ''It was when she agreed to go to his house that he gave her the new, shiny Segway.
''He thought a Segway would be a chance to prove they can have good, clean fun together, and she thought that was a really sweet touch.''
The 1969 session, including the only known recording of 'Sunshine Woman' by the band, will be included on a re-issue of 'The Complete BBC Sessions'...
The 55 year old actor joined Chris Martin and co. on stage in New Jersey to perform 'Earth Angel' and 'Johnny B. Goode'.
Bjork Digital comes to London's Somerset House in September, along with a single live show at the Royal Albert Hall.
Kim Kardashian released an audio excerpt from a phone call between Kanye and Taylor Swift over the lyrics of 'Famous' - but if it was recorded...
There's very much a strength of conviction in remaining what you were, but arguably more so in becoming what you want to be.
The BBC drama starring Aidan Turner returns to BBC One on September 4th.
Guns N' Roses were detained at the Canadian border last week for gun possession but they're adamant the weapon didn't belong to them.
With virtually the same blend of wit and idiocy as the 2001 original, this fashion-scene...
Though Derek and Hansel have left the world of fashion modelling behind them, a part...
Derek, Hansel and some other familiar faces are back in Zoolander 2! After offering their...
After a disastrous return to the fashion industry following his retirement, which almost ended in...
When Justin Bieber was discovered by Scooter Braun and Usher Raymond after performing his songs...