It's a partnership that has lasted longer than many marriages. Although, according to Anton Du Beke, that may well be the secret to his 20-year partnership with dancer Erin Boag.

'Erin would probably say it's the fact she married somebody else,' says Du Beke with a laugh. 'And I don't think I can blame her for that.' Instead, the duo has enjoyed a professional relationship that took them from competitive ballroom dancing to prime time television via Strictly Come Dancing.

About to embark on their ninth theatre show, Swing Time, filled with classic numbers such as 'I Could Have Danced All Night' and 'I've Got Rhythm', Du Beke is the first to admit that Saturday night TV has done dance the power of good.

'Before Strictly, nobody would have come to our show,' he says. 'And nobody would have done a ballroom show on stage. Dance has always been at the bottom of the arts leader board, as it were – ballet did its thing, then there was musical theatre, contemporary and street dance, and it was all a bit niche.

'But because of Strictly, those worlds have come together and it's introduced new audiences to dance.'

Swing Time is a case in point, with Anton and Erin surrounded by musical theatre dancers, vocalist Lance Ellington and a 25-piece band. So when the two stars glide out dressed to the nines, ballroom has a chance to shine.

'Our dancers are all from musical theatre,' explains Du Beke. 'not straight ballroom. Which I think is nice, because then when the ballroom dancing happens, it's somehow a bit more special.

'And then we'll have songs, duets and three-handers with Lance, because two hours is quite a long time just to do ballroom. It also allows me to be a bit indiscreet about people on Strictly – and I think the audience enjoys that because it's a bit of fun.'

Usher Hall, Edinburgh, 4 Mar, 7.30pm; Glasgow Royal Concert Hall, 5 Mar, 3pm.