"Back in 2009, I'd be running the early-morning group with the likes of Ashley Beck, Eli Walker, Tom Prydie, Matthew Morgan, Tom Habberfield and Sam Davies, young academy players at the time.
"It would be a 7.30am skills group, lasting for about 90 minutes and complete with lots of conditioning games and mini-games.
"Jerry would turn up wanting to join those games.
"It was awkward because I'd know that he'd have a full day of training ahead and the conditioners and the medics wouldn't want him to overload by doing stuff beyond his normal routine.
"I remember saying to him: 'Look, Jerry. This is really awkward but you are going to have to concentrate on your own sessions during the day. I'll have to politely say 'no'.
"But on one occasion I can recall Jerry giving me a glare as if to say: 'No, I'm doing the games.'"
Collins made 56 appearances for Ospreys from 2009-2011, where he won the Ospreys' Players' player of the year award in the 09/10 season.
"You couldn't help but enjoy his appetite to be involved, so I'd let him take part on the understanding that he didn't overdo it," Rees told Wales Online.
"He'd love to play the little games we used to do.
"I don't know whether he was sweating off the night before or it was his own little release, but normal rules didn't apply to him and an hour later he would still train as effectively as ever with Scott Johnson and the senior group.
"He'd get his weights done and get his speed done. So his amount of training was phenomenal.
"He just did things differently."
