But the 25-year-old could not replicate that success upon his return to domestic duty with Gloucester.
The team struggled to make an impression all season yet Fanolua, a centre who played for ten years at Gloucester, says Twelvetrees can get back to his best.
"Billy is a top class player, who is a bit down on confidence at the moment, but I'm fully confident that he will bounce back and retain his shirt with the England team," said Fanolua.
"He's a leader for Gloucester and he's been in the Premiership for a while now. He's an experienced player and that's what Gloucester needs - the more experienced guys need to stand up and be counted to lead from the front."
Twelvetrees, too, admits it's an important campaign to stamp his mark for his club.
"It's a massively important year for us as players," he told the Gloucester Citizen. "We have to get the belief back in the squad and it will take a massive effort from the boys to repay the fans' faith in the squad."