LIZZIE Jones – widow of tragic Keighley Cougars star Danny – performed at the rugby league World Club Series.
She sang before the games at St Helens on Friday, Wigan on Saturday and Leeds on Sunday.
"It was lovely to perform at all the different stadiums," said Mrs Jones, a professional singer.
She launched a fundraising campaign last week to buy defibrillators for rugby clubs across the UK.
She aims to raise £50,000 and have the life-saving machines installed at half of all junior and community clubs within a year.
Danny Jones died last May after collapsing during a Cougars match against London Skolars.
It was later discovered the 29-year-old Welsh international had an undetected hereditary heart condition.
His shock death sparked a wave of support throughout the rugby league and wider sporting community, and several hundred thousand pounds were raised in his memory.
The defibrillator appeal is being run in association with the RFL Benevolent Fund.
Mrs Jones has already successfully campaigned for cardiac screening to become mandatory in the top three leagues.
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