DENVER (AP) — President Barack Obama says at the start of the first presidential debate that 20 years ago he "became the luckiest man on earth" when married his wife, first lady Michelle Obama.

Republican rival Mitt Romney congratulated the Obamas at the start of the debate, joking that, quote, "I'm sure it's the most romantic place you can imagine, here with me."

The Obamas are celebrating their 20th wedding anniversary at the Denver debate. The first lady is in attendance.

Obama called the first lady "sweetie" and wished her a happy anniversary from the debate podium.

He says, a year from now, quote, "we will not be celebrating it in front of 40 million people."