Bones star David Boreanaz has hinted that the show could be approaching its end.

The actor, who plays Seeley Booth on the TV show indicated on social networking site, twitter, that the Fox drama’s eighth season could be its last.

He wrote: "SDCC 2012 shld be a blast and quite possibly the last for Bones? Farewell tour? Look forward to seeing everyone there."

He later added: "Let's put this in sports terms. I'm a free agent after this season. So the Bones fair well tour is in full-swing.

"You must always keep your options open and ready for new challenges. The fear is the unknown and that's exciting."

Bones was officially renewed for an eighth season in March.