The 34-year-old lock, part of Australia's victorious 1999 World Cup team, was contacted by Wallabies coach John Connolly as he arrived in Melbourne to play with the Rebels in the Australian Rugby Championships.
"I saw the message and thought 'What's this about?'" Cockbain explained. "I was thinking maybe it was about some coaching with the Wallabies.
"But then Knuckles (Connolly) explained they had a few injuries and they were bringing a few guys in to train with the team next week and he'd like me to be one of them.
"I rang my wife and told her and she didn't believe me.
"I used to joke about that's why I'm still playing - to make it to the Rugby World Cup in 2007," he said.
"I'm very shocked but I know a lot's still got to happen for me to actually go to France."
The call-up came after Connolly watched Cockbain put in a storming performance in Brisbane club rugby on the weekend.
When asked if he knew he was playing himself back in to the Wallaby squad, Cockbain remarked: "Well if I was, it certainly wasn't intentional.
"I really went out and just had a bit of fun like always.
"I play as hard as I can and Knuckles was in the crowd and obviously liked what he saw.
"I'm not getting too ahead of myself at the moment. I'm just training with the team. I'm not on a plane (to France) yet."
Meanwhile, incumbent Wallabies lock Nathan Sharpe, who was voted the team's best player of 2007 on Monday, said he would trade his prestigious John Eales Medal to hold aloft the Webb Ellis trophy in October.
"It's a tremendous honour to be recognised as an individual but I'd trade it in a heartbeat to win some silverware with this team," Sharpe said upon accepting his award on Monday night in Brisbane.
"In any industry or sport you love to feel part of the team and (like you're) contributing something and when you win an award like that, you certainly do.
"It's a tremendous feeling in the side at the moment and we're looking forward to approaching the road to France."