Sydney-bound AFL superstar Lance Franklin says he decided only after Saturday’s grand final to join the Swans and has known of their interest for only a fortnight.

Franklin, 26, admits it’s “unbelievable” that the Swans have offered him a nine-year deal, pointing out that, assuming he completes it, he’s currently only halfway through his career.

“I’ve been playing for nine years now,” Franklin told Fox Sports on Wednesday.

“To get another nine years is something unbelievable.”

Asked if his body could hold up that long, he replied: “Hopefully.”

While Franklin had been widely expected to join Greater Western Sydney since putting contract talks on hold before the season, he insisted it was only after the grand final that he made up his mind to leave Hawthorn.

“I truly hadn’t made my decision before the grand final,” he told the AFL website on Wednesday.

“I made my decision pretty much at the last minute so Sydney, to their credit, have done a good job and I’m happy to be there.

“I only found out the last couple of weeks, literally, that the Swans were interested.

“From there I pretty much committed in the last week and said yeah, I’ll head up and play for Sydney.

“What a great club they are.”

GWS were shocked on Tuesday to be trumped by the Swans.

Franklin said telling his Hawthorn premiership teammates he was leaving had been heartbreaking.

He also praised coach Alastair Clarkson for the way he handled the news.

But Franklin said it was a scenario the AFL industry had to get used to.

“This is what the players wanted, free agency, and this is where footy’s going these days,” he said.

“I’m excited about the new change. It’s going to be a little bit different up there for me but I can’t wait to get up there.”

While Franklin has agreed to terms with the Swans, the AFL is investigating the deal, which can not be lodged officially until the free agency period opens on Friday.