The movie star duo were joined by their respective partners, Ashley's Australian boyfriend Paul Khoury and Kellan's brunette female friend, as they took in the Lakers game at the Staples Center in downtown Los Angeles.
And it seems that Joe knows exactly how to treat a girl to a perfect day out.
The two first went for some lunch before hitting the shops for a few hours of retail therapy.
Ever the gentleman, the 21-year-old singer was later seen carrying their many purchases to his waiting Porsche.
The couple then headed off to celebrate Joe's little brother Frankie's 10th birthday.
Rumours started about the couple dating after they were spotted together enjoying a romantic dinner at The Ivy in London back in July. Despite the perfect daytime combination of lunch and then shopping Greene looked decidedly glum Ashley, 23, was in town to attend the premiere of Twilight, in which she starred as Alice Cullen, and Joe was there to support his brother Nick in his stage debut, appearing in Les Miserables.
Jonas had been dating teen sensation Demi Lovato whom he split from in May.
Hopefully they split on good terms though, as Lovato is currently touring with the Jonas Brothers.
Meanwhile, it seems things are starting to get serious between the Ashley and Joe. News reports that Greene recently took Jonas home to meet her parents in Jacksonville, Florida. magazine Life & Style reports that Joe has ditched his ring since hooking up with Greene.
Shop till you drop: The couple certainly know how to give their plastic a good workout as they were laden down with bags And then there's the matter of the purity ring that Joe and his two brothers, Nick and Kevin vowed to wear as a symbol of chastity until they married.
Jackson - who is best known for playing Jasper Hale in the Twilight Saga movie series - is said to have traded in two of his cars for a more family-friendly Lexus Hybrid SUV in preparation for the new arrival.'I have loved my character and I have loved playing Jasper through the years, so if there is an extension of playing Jasper - more so in his own element, maybe go back in time and do a vampire western, show Jasper where he came from - I would be down for that.
: “I’m sort of dating someone — she’s an actress.” Inside the party, Eggold, 24 and Greene, 21, didn’t keep their new relationship a secret at all.