Robert Pattinson & Kristen Stewart NOT invited to 'Twilight' star Kellan Lutz's birthday, break-up too awkward? Actor parties in Thailand with sexy model, baby elephant & 'bros'

"Twilight" hottie Kellan Lutz just celebrated his 29th birthday in Thailand - and Robsten was not invited to the epic celebrations.

Lutz partied with a sexy model, baby elephant, bros, cake, and vast amounts of alcohol at the infamous Nikki Beach Phuket. Check out the photos here.

Robert Pattinson and Kristen Stewart are both VERY busy with their separate movie careers right now. The British heartthrob is currently in Toronto filming "Life," and the "SWATH" starlet enjoying her self on the set of "Still Alice." Wonder if they got an invite from Lutz and they both just couldn't make it.

The "Twilight" series finished filming awhile ago, so it's unlikely that Lutz remained too close with the on-and-off again couple. It's no big surprise that neither R-Patz or K-Stew showed-up in Thailand for the festivities. But who knows? Maybe Lutz felt awkward inviting them both after their rather highly-publicized break up... or worse, inviting just one person and not the other.

No hard feelings - it looks like Lutz had a blast. But the question still remains, Robsten fans - should Pattinson and Stewart get back together once work simmers down?

UPDATE: Kristen Stewart wants Robert Pattinson back, starlet begs 'Twilight' heartthrob to celebrate 24th birthday in LA amid 'Life' movie filming? 'Always talking'