Bright lights and big name stars were the order of the night as Colin Farrell and Claudine Keane led Team Ireland into the Los Angeles Memorial Coliseum, alongside John Treacy who won silver at same venue in the 1984 Olympic Games.
The 88 Irish athletes are among the best supported in LA and it's in no small part thanks to the local ex-pats.
True Detective star Farrell said he was "so excited" to be involved and witness "the spirit of competition".
"So many athletes from all over the world coming together and the Irish team front and centre. Meeting all of the athletes and walking out amongst the Irish team is such a great honour. Let's go Ireland. Let's go world," he said.
LA Galaxy star Robbie Keane couldn't make last night's opening ceremony, which featured Stevie Wonder and Michelle Obama, but he hopes to do a run-out with the Irish 11-a-side soccer team ahead of their games later in the week.
His model wife Claudine - who announced yesterday that she's pregnant with the couple's second child - took his place just hours after posting a video online of her telling the couple's son Robert (6) that his "dream" of having a brother or sister would come true.
Robbie flew to Houston on Friday where he will play a mid-week game in the MLS All-Star team against his old club Tottenham.
He told the Sunday Independent that the couple are loving life in LA and he expects that they will be settled there for "a few years" yet.
"I do like the lifestyle. It's a good lifestyle. It's very relaxed for the family. Lots to do outdoors, especially with my son. He likes going to the beach," he said.
Ireland's top goal scorer has been involved with Special Olympics for over a year and helped train the soccer team during a visit home to Dublin earlier this year.
"I'm excited to be part of it. For the athletes, they are just ready to play now. It's been a long build up but they are here now," he said.
Along with the athletes the Team Ireland delegation is made up of 40 managers and 155 volunteers.
The squad will take part in 13 different sports including aquatics, basketball, bocce, equestrian and kayaking.
The Opening Ceremony was extra special for Oliver Doherty (38) from Buncranna in Co Donegal who was one of four previous medallists to take part in the official raising of the Special Olympics' flag. The golfer won gold at the 2003 World Games.
For John Treacy too it was an emotional evening as he walked the track where he finished his famous marathon run 31 years ago.
"Being back in the LA Coliseum brings back so many incredible memories and emotions. To represent your country on the world stage is an incredible experience for all involved and I would like to congratulate all the athletes and their families here today," he said.
"I have no doubt that they will be wonderful ambassadors for our country and they will perform with distinction throughout the course of the games."
Ireland's Ambassador to the United States Anne Anderson and the Consul General for the western United States Philip Grant, who was widely praised for his efforts during the recent Berkeley tragedies, have also been involved in the build-up.
Others who have travelled over for the games include former Justice Minister Nora Owen and Today FM presenter Ian Dempsey.
Ms Owen, a member of the Council of Patrons of Special Olympics Ireland, told the Sunday Independent that she believes much of the awareness of the movement can still be credited to the massive success of the 2003 games in Ireland and the specular opening ceremony in Croke Park.
"I'm delighted it has made an impact here with the people in Los Angeles," she said, noting that the games will be the single biggest event in the city since the 1984 Olympic Games. On the plane from Philadelphia to Los Angeles the pilot wished 'Team Irish' well and there was a big cheer. So there is that kind of atmosphere.
"These are true athletes. These Special Olympians are just magic," she said.
The retired Fine Gael minister was particularly keen on Stevie Wonder's performance at the Opening Ceremony, where the guest list included singers Avril Lavigne and Nicole Scherzinger, TV presenter Jimmy Kimmel, actress Eva Longoria, and Olympic star Michael Phelps.
Ian Dempsey, who will be presenting his popular Today FM Breakfast Show from LA this week, has attended every games since Dublin.
"It's a great buzz. We love doing the show from the Special Olympics because it means so much to everyone to get all the messages back home to family and friends who are waiting on news," he said.
More than 7,000 athletes from 177 countries are taking part between today and August 2, making the Special Olympics one of the largest sports events anywhere in the world in 2015.
Matt English, CEO Special Olympics Ireland, said Ireland stands out because of the large number of volunteers and the LA links with Treacy, Farrell and the Keanes.
"Special Olympics Ireland has always relied on the support of friends across many different spectrums. Having individuals like John Treacy, with his connection to Los Angeles and his immensely supportive role through the Irish Sports Council; Colin Farrell, as a well-known actor who has lent his support time and time again to our movement, and Claudine Keane, who together with her husband, Robbie, helped galvanise our fundraising campaign to get Team Ireland to the World Games, is hugely important to both the organisation, and our athletes," he said.
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