Donncha O’Callaghan will realise a childhood family dream when he makes his Barbarians debut against the England XV at Twickenham on Sunday.

The Munster and Ireland lock broke his 101 Greatest Tries video as a youngster playing and replaying Gareth Edwards's classic 1973 Barbarians score against the All Blacks.

O’Callaghan’s older brother Ultan won Barbarians selection to face the Combined Services in 2002, and now the British and Irish Lions secondrow admitted delight at following suit.

“We were a rugby-mad house growing up,” said O’Callaghan after winning selection in a line-up boasting more than 700 caps.

“We had the 101 Greatest Tries video, and I remember after about three months you couldn’t watch the 1973 try against New Zealand any more because the tape was so worn, from just rewinding over and over.

“Growing up with three older brothers, when we played rugby in the garden it was always the Baa-Baas versus Ireland, because no one ever wanted to be Scotland or England!

“Even back then you threw the ball around when you did it. That’s the tradition.

“When rugby’s getting so professional it’s so heartening to see the amateur values that we have to hold onto. I’m delighted: I was ready to swim over when I got the call.

“My brother beat me to it, but the family pride when he was selected was amazing.

“I watched him play over the years and always thought he was good enough to be knocking on the door for more honours with Munster and Ireland, but it never came. So for him to get the Barbarians call was great.

“It’s an honour to be thought good enough even to be in the room with players of this calibre frankly.”

O’Callaghan admitted the weight of Barbarians tradition brings him out in a cold sweat when he considers doing justice to the greats to have sported the black and white since 1890.

The 94-cap Ireland lock said he will be happy to emerge from Sunday’s clash with the respect of his world superstar team-mates.

“You feel the pressure to perform as well, that you owe it something,” he said.

“That’s a weight on your shoulders. The big thing is trying to win the respect of the dressing room when put alongside world superstars.

“The onus is on us playing now: we have to really put value on it in our time when we get a shot.

“It’s an incredible club when you think about it: the Barbarians have more wins over New Zealand than Ireland. That pressure gives me sweaty palms straight away.

“And that’s what makes you play better in matches, you need that.”

Teetotal O’Callaghan admitted he is not in the free-running Barbarians mould, but has no intentions of winding down despite his advancing years.

The 35-year-old has not given up on forcing his way back into Joe Schmidt’s Ireland squad for Rugby World Cup 2015, as well as setting sights on more Munster glory.

“Two of the big values you need for the Baa Baas I might not have had: I’m a non-drinker and I’ve spent my career hitting rucks and mauling!” he said.

“So I’ve been getting a bit of stick from the Munster lads for that, they’re saying I’m not really cut out for it.

“I’m as competitive as ever, I love it, I bounce out of the bed to Munster in the mornings, it means an awful lot to me.

“If I wasn’t enjoying it I would gladly step away. Munster means so much to me it’s easy to go in every day.

“I’ve two more years on my contract and I want Munster to have success and win trophies in that time.

“Semi-final defeats are scars that hurt more months down the line than they do on the day.

“I’ve been involved in 11 Heineken Cup semi-finals and only grabbed two.

“You have to be a little selfish when it’s your time and grab as much as you can.

“Munster’s my main focus, but I do still have ambitions with Ireland especially heading into the World Cup year.

“I might need the rub of the green but I’ll be honest my mentality’s no different for cap number 95 as number one: I would chew up the road for it.

“People might say that’s delusional, but I’ll keep thinking it!”