Watch Jon Jones, Francis Ngannou face-off for the first time since UFC departure (Video)

It's the one that got away.

Jon Jones and Francis Ngannou were supposed to fight under the UFC banner, or at least that's what we were told as the negotiations between the two fighters began to crumble apart.

Jones is now the UFC heavyweight champion and Ngannou has signed with the PFL but on Friday night the pair crossed paths.

Jones was cage side at PFL 5 cornering the main event fighter Maurice Greene. Ngannou was there as an invited guest, he's yet to make his promotional debut.

The pair had a moment, which was captured on video and quickly went viral.

Jones could be heard telling Ngannou “you don’t want no smoke” as PFL president Ray Sefo looked on.

It's unlikely the UFC would ever agree to a cross promotion ... but here's to hoping.