The Wales centre starred for the famous tourists four years ago in South Africa and is a favourite to feature in the Test matches Down Under.
But 26-year-old is well aware of the competition he faces from Wales teammate Jon Davies, Ireland legend Brian O’Driscoll and England powerhouse Manu Tuilagi.
“The talent in the centre is pretty special and it’s so competitive,” said Roberts.
“I am taking nothing for granted and I know I will need to work extremely hard to win a Test place – the other guys in my position are serious rugby players.
“The competition for places is pretty intense; you don’t go out with the aim to achieve Player of the Series or even to start all of the Test matches.
“There are no guarantees on a Lions tour and everything needs to be earned.
“If it happens it happens. I picked up that accolade in 2009 as part of a very strong team.
“But I was just gutted we didn’t win the Test series in 2009 though – that was my biggest regret looking back on it.”
The memories of ‘The Battle of Pretoria’ still cut deep for Roberts and he insists Test series glory is the be all and end all Down Under.
“I have never known a changing room quite like it after the second Test – it was pretty unique,” added Roberts.
“So the aim is to go there and win the Test match. There are no individual goals so to speak – it’s going to be a huge collective effort.”
Roberts is embarking on a life-changing summer in which he will also join Racing Metro.
He could be forgiven for letting his mind drift to his impending move to France but insists his sole focus is on Australia.
“For me, I have had 26 years in Cardiff, it is time to fly the nest and try something new,” added Roberts.
“I’m just going to be a free spirit for a year or two. It’s a new group of people and team-mates and I’ve got a make an impression as well. So that’s a challenge in itself.
“The Lions is first though so anything like house-hunting and moving will be done afterwards.
“I need to start learning my French. I’ve got no direct ties now in Cardiff. I suppose I’ve got my house but university is done.
“But for the time being it’s all about the Lions and taking each match as it comes.”