Credit: Jean Baptiste Lacroix/

When Nicole Richie and Joel Madden tie the knot -- reportedly this summer -- they'll have a world-class balladeer to serenade their first dance: Richie's dad, Lionel Richie.

"My happiness for Nicole and Joel knows no boundaries," Richie tells in a statement. "They have given me two beautiful grandchildren, Harlow and Sparrow, and have proven to be great parents."

Nicole is the adopted only child of Lionel, 60, and his ex-wife Brenda.

"I am not sure who is luckier, Nicole and Joel to have each other, or me, to have both of them in my life," the "All Night Long" singer says. "I cannot wait to give away the bride!"

After Madden, 30, announced his engagement to Richie, 28, via Twitter on Monday, his bride-to-be told David Letterman the good news at a taping for the Late Show with David Letterman. (The episode will air this Friday.)

"We actually recently are engaged!" she told the comic. The star and fashion designer was photographed in NYC Monday wearing an enormous engagement ring.

But Richie didn't mention the big news during a Tuesday appearance on Live with Regis and Kelly -- or on her always-active Twitter account.