16 May 2016 Last updated at 06:45 BST
The athletes will wear the outfits at special events at the games in Rio this summer.
Children across the UK were asked to send in their messages of support for Team GB and then 10 of the best were chosen.
Leah was at a special photo shoot to meet the athletes wearing their new gear.
This report contains some flash photography.

A grant of £1.78m from the Heritage Lottery Fund (HLF) will be used to create Scotland's first centre for children's literature and storytelling.
It is part of £4.8m the HLF is donating to five projects across Scotland.
Others include Campbeltown Picture House, which will receive £1.1m to fund restoration and improvements.
The Peter Pan Moat Brae Trust hope to promote "creativity, imagination and play" with its plans for the house and garden where Barrie played as a child.
In November it received £687,500 from Creative Scotland. The HLF grant moves the trust closer to its goal of raising £5m for the project.
Actress Joanna Lumley, who is a patron of the trust, said: "This grant will make a sensational difference to Moat Brae and the plans for the future of the Peter Pan Moat Brae Trust.
"It means that we can now move swiftly towards our goals of restoring the house and gardens in readiness for its role in the literary life of children in Scotland.
"Our aims are to nurture the memories of past writers and to encourage the emergence of new talent, to respect our extraordinary literary inheritance and to enable children's imaginations to fly, like Peter Pan."
Work is expected to get under way next year at the building, which was home to JM Barrie's childhood friends while he was a pupil at nearby Dumfries Academy.
An exhibition space will be created within the existing building and two extensions will house visitor facilities including a shop and cafe, and a learning and education suite.
Trust chairman, Dame Barbara Kelly, said: "I believe Moat Brae will create a major attraction and focus for local, national and international visitors.
"It has massive potential to contribute to the local economic, social and cultural regeneration of Dumfries and has the ability to attract much-needed inward investment and could create up to 35 new jobs."
Colin McLean, head of the HLF in Scotland said it was delighted to support the "ambitious" and "inspirational" project.
"A new breath of life has the potential to transform them into a visitor attraction that could boost the town's tourist economy and inspire children today and tomorrow, as they once inspired JM Barrie," he said.
Other HLF grants have been distributed to Heritage Inverclyde, Merkinch Welfare Hall and Wildcat Action.

Warwickshire Police said officers were called out from 10:30 GMT in advance of the Blue Square Bet Premier League game between Nuneaton Town and Lincoln City.
British Transport Police and officers from the West Mercia and West Midlands forces helped in the operation.
Officers in riot gear began making arrests at The Granby pub from 15:20. A total of 62 people were detained.
They were taken by coach to Nuneaton police station where they were being interviewed.
Ch Insp Adrian Knight, who was leading the response, thanked his colleagues for their work on what had been a "particularly challenging day", adding: "This operation was a true collaboration utilising resources from across the region."
He went on: "It was important to take a positive approach from the start of the operation and as a result of that approach a significant number of people have been arrested for serious offences and will now be processed.
"Warwickshire Police is committed to protecting people from harm, whether they live in the county or are visiting, and we will not tolerate any behaviour which puts them at risk.
"Anyone intent on causing trouble in Warwickshire should be aware that we will deal with them robustly," he added.
Nuneaton went on to win the game 1-0.
Team GB have been showing off their new suits that have good luck messages from children printed inside.
[NEXT_CONCEPT]
Plans to preserve a Dumfries house which inspired JM Barrie to write Peter Pan have been given a major financial boost.
[NEXT_CONCEPT]
Dozens of people were arrested after police in riot gear were deployed ahead of a football match in Nuneaton.