SBW: Biggest cheer was finding out sister Niall made squad

All Black Sonny Bill Williams has revealed his feelings when told he was going to the Rio Olympics as part of the men's sevens squad, and said the biggest cheer in his household came when the news was confirmed his sister Niall was going too.

It was confirmed today at an announcement at Eden Park that the two Williams siblings would wear the black jersey at the Games next month, with Niall selected in the New Zealand women's squad.

For Sonny Bill, 30, a two-time World Cup winner, former league player and keen boxer, it is the continuation of an incredible sporting story. For Niall, 28, it is the culmination of a dream which saw the mother of two young girls switch from a successful touch background to the crash and bash of sevens rugby.

"Just seeing where she's come from, a mother of two - when she first started her journey she wasn't contracted so she would get up in the early hours and do her training and look after the girls and then train again at night. I'm pretty proud of her," he said.

"I was happy when I got the phone call but the biggest cheer we had in our house was when we found out my sister made it, so we're really proud of her."

The two Williams will be part of the two 12-player squads travelling to Rio to play sevens rugby for the first time at an Olympics. Rugby - the full version - was last held at the global tournament in 1924, with the United States taking the gold medal.

Sonny Bill Williams. Photo / Brett Phibbs

The pair will be part of a New Zealand Olympic team of 200 athletes, with a further 150 people travelling as support staff. The Games will be attended by 105 countries and will be watched by an estimated 4 billion television viewers.

Sonny Bill said he felt for those, including his former Chiefs teammate Liam Messam, who didn't make the squad.

"I'm really proud of making this team, but I'm also very aware of the boys who didn't make it. I'm feeling for them.

"I've spoken to [Messam]. It's pretty tough; I feel for the bro, he's like a brother. I feel for him and I feel for a few of the other boys who didn't make it as well. But in saying that we've got to show our respect for them by competing well and doing our best."

Sonny Bill, who has been in sevens mode since last year's World Cup, said after travelling around the world representing New Zealand on the circuit this year that the shortened version of the game held an even greater appeal.

"It's lit a fire in me that I haven't been able to put out. It's a bit like boxing when I started boxing. I've signed on with NZ Rugby for the next three years but in my contract I'm allowed to play sevens as well in the off season. That's how much I've grown to love it. What excites me? I guess from a spectator's point of view it's non-stop action and the challenge for a player is you have to work that much harder."