Kevin Richardson flew his kids over to London for Backstreet Boys second show at The O2 on Tuesday night (18.06.19).
The 47-year-old hunk revealed on stage that Maxwell, five, and Mason, 11 - whom he has with wife Kristin Richardson - were in the audience for their "first show" of the 'DNA World Tour' after finishing school for the summer.
He told the sold-out arena: "They've just finished school... It's their first show."
And the youngsters no doubt giggled during the set, as their dad cheekily got changed behind a screen with his bandmate AJ McLean, 41, at one point, before the pair started throwing their signed boxers into the audience to "give back" to the fans who have thrown their bras and panties on stage over the years, sending the front rows' pluses through the roof.
The moment segued into the pair teaming up for a duet of their "favourite" song from their latest LP,'DNA', 'Passionate'.
The US boyband - who formed 26 years ago - put on a flawless show from start to finish, comprised of an impressive 33 songs.
As well as performing all the hits, including 'As Long As You Love Me', 'Larger Than Life', 'Everybody (Backstreet's Back)' and 'Show Me the Meaning of Being Lonely', Nick Carter, 39, performed a solo version of 'The Way It Was' and Howie Dorough, 45, earlier performed 'Chateau' and Brian Littrell, 44, wowed fans with his own rendition of 'Nobody Else' from the record.
The humble 'I Want It That Way' hitmakers regularly stopped to thank the crowd for making their dreams come true, and Nick stumbled on his words at once point and admitted it was because he was so "overwhelmed" to have sold-out The O2 two nights running.
Backstreet Boys continue the European leg of their 'DNA World Tour' on Thursday (20.06.19) at the Lanxess Arena in Cologne, Germany.
Backstreet Boys' setlist:
'I Wanna Be With You'
'Don't Want You Back'
'Get Down (You're the One for Me)'
'Show Me the Meaning of Being Lonely'
'More Than That'
'The Way It Was'
'Shape of My Heart'
'Quit Playing Games (With My Heart)'
'As Long As You Love Me'
'Don't Wanna Lose You Now'
'I'll Never Break Your Heart'
'All I Have to Give'
'Everybody (Backstreet's Back)'
'We've Got It Goin' On'
'It's Gotta Be You'
'That's the Way I Like It'
'Get Another Boyfriend'
'I Want It That Way'
'Don't Go Breaking My Heart'
'Larger Than Life'