There was no hiding Boris Becker’s elation at the prospect of becoming a dad with wife Lilly Kerssenberg when they attended an awards ceremony on Monday night.

But as he beamed down at his partner's bump, there was one thing Boris wasn’t revealing – the baby’s sex.

Though the former tennis ace already knows whether it’s a boy or a girl, he’s promised to keep it a secret from Lilly.

“Boris does know, and I told him that he should not tell me,” said Lilly, who wore a stunning floor-length sequinned gown at the event in Kitzbuehel, Austria.

“With my luck, I'll end up asking him soon, but I will try to wait as long as possible.”

The couple married in a beautiful Alpine wedding in Saint Moritz, Switzerland, in June.

Boris already has two children from his marriage to Barbara Feltus, and another with model Angela Ermakova.

Photo: � Rex