Westlife and their fans created a world of their own at two sold-out gigs at London's Royal Albert Hall on Monday and Tuesday.
It wasn't just trawls of fans that passed through the venue, however, a host of well-known faces were also dotted throughout the audience, inluding former One Direction star Niall Horan.
Find out what other celebrities turned up at Westlife's performances in their glad rags...
After the fact, Cecelia wrote: 'What a spectacular night at Royal Albert Hall celebrating Westlife. Stunning dreamlike night!'
On night one, Westlife were joined on stage by The Voice star Kirsten Joy, who acted as Mark's stand-in while the band sang his 'favourite song'.
Speaking to the crowd before launching into Flying Without Wings, Shane said: 'I want to take a minute to talk about Mark, who unfortunately is not with us tonight. But we love him, we miss him, and we cannot wait to have him back on this stage with us...
'The good news is he's obviously on the new music, which you've heard already, Chariot. And, the next album as well, we have a new album coming out in February.'
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'So this next song, I want to dedicate it to Mark because it's Mark's favorite song. That might give you a hint. It's a beautiful song. So tonight we'd like to dedicate it to him, and I'd like to invite Kirsten Joy down to sing it with us.
'This song is probably the song that changed our whole career,' he admitted, before he joined Kirsten, Nicky, and Kian in song.
Gushing over her 'dream come true', Kirsten later penned: 'It'll take me a while to get over this one! Singing with @westlife and the @royalphilorchestra at the Royal Albert Hall last night was a DREAM. COME. TRUE. Thank you.'
On night two, Katherine Jenkins served as Mark's stand-in during Flying Without Wings. The Welsh singer, 45, looked fantastic in a sparkly strapless jumpsuit, which had a cool detachable train.
Sharing photos from the night, the Neath native penned: 'An unforgettable night celebrating Westlife’s 25th Anniversary at the Royal Albert Hall. Always the loveliest lads - and what a treat meeting so many of the family backstage!
'Thank you for trusting me with You Raise Me Up. I loved every minute of singing with you!'
Of course, what would a Westlife gig be without the Westlife WAGs in attendance?
Shane Filan's wife, Gillian, Nicky Byrne's wife, Georgina, and Kian Egan's wife, Jodi, were all front and centre to support their hunky men at Royal Albert Hall.
Georgina stood proudly with her twin sons, Jay and Rocco, 18, and her daughter, Gia, 12, at the gig. On night one, she stunned in a pink Karen Millen number, which she previously wore to a family friend's winter wedding.
On night two, Gillian looked phenomenal in a full-length gold dress with long sleeves and a deep V-neckline. She was wearing the Margot sequined gown by designer Jenny Packham, which is currently on sale for €2,470, down from €3,500.
And Jodi, as usual, looked incredible in an all-black number, with cool sparkly detailing. She twinned with her three sons, Koa, Zekey, and Cobi.
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Westlife pay tribute to Mark Feehily as they use stand-in at Royal Albert Hall
