Photo: Steve Marcus

Justin Timberlake, left, and touring pro John Daly wait for the start of a pro-am event Monday at TPC Summerlin.

Don’t ask how, but one of America’s hottest actresses went almost completely unnoticed in front of a few hundred young fans Wednesday during the PGA tour’s Celebrity Pro-Am event at the TPC Summerlin golf course.

First the young starlet concealed her near flawless face under a well-placed red umbrella. A beige dress didn’t draw too much attention, and dark sunglasses rounded out the guise.

Of course, it didn’t hurt that Jessica Biel’s boyfriend, Justin Timberlake, also had every eye on the course watching his every move.

“Sorry I’m not doing any interviews today,” Biel told a reporter politely.

She didn’t have too. Timberlake was the main attraction — even if good friend Ellen DeGeneres did her best to detour some of his fandom (which included a healthy dose of young women in very revealing, um, golf outfits) her way on the first hole of the Justin Timberlake Shriners Hospitals for Children Open.

“It was a perfect day off,” Timberlake said, after completing his foursome round with professional golfer Fred Couples and amateurs Matthew Sheasby and Jordan Levinson.

While his group didn’t win the low-ball event (pros Tommy Armour III and Ryan Moore led their respected foursomes to a first-place tie with a 20-under score of 52), Timberlake said the real winners during the week-long event are the children that benefit from the tourney’s sponsor.

“It’s a wonderful, wonderful organization,” said Timberlake of the Shriners, who he paired up with last year after telling PGA officials he wanted to play a part in one of their events.

“So to me, when the Shriners Hospitals for Children got involved with the Vegas tournament, this all just became a no-brainer.”

Such sentiment was shared by the handful of celebrities that showed up, which included movie stars Luke Wilson, Greg Kinnear and Josh Duhamel, along with comedian George Lopez, Olympic swimmer Amanda Beard, former 'N Sync member Chris Kirkpatrick as well as PGA pros John Daly, Davis Love III, Zach Johnson, Rocco Mediate, Jesper Parnevik and Mike Weir.

“Obviously with the stars, not only Justin, but some of the other people, actors and athletes that showed up to support the event, I think it’s wonderful,” said defending champ George McNeil.

Wilson was content with just staying out of the way of the pros.

“It’s kind of funny because I’m just trying to keep out of their way, but a bunch of the business guys get right in there and aren’t afraid to ask for golf tips,” said the star of Old School. “It’s pretty funny to watch.”

Photo: Erik Kabik/Retna

Justin Timberlake and Jessica Biel rally for Obama.

As was DeGeneres, who kicked off the days festivities by singing her own version of “Sexy Back,” while she toted around a boom box on the putting green.

As the gathered crowd of a few hundred waited for Timberlake to tee off on the first hole, DeGeneres pestered him with a bullhorn. The two playfully exchanged barbs as they walked down the fairway. The talk show host, who was taping segments for a future show, also pulled off a beach skit from a bunker, gave Timberlake a hockey-sized putter, and poured him a drink at a make-shift bar after the first hole.

“He’s my good friend and he asked me to come out here, so of course, I did,” DeGeneres said.

Also on the green was close friend and former band member Kirkpatrick, who wasn’t surprised that Timberlake, who is hosting a concert with special musical guests in conjunction with the golf event Friday night at Planet Hollywood, took up the tourney for a good cause.

“He’s always been a big supporter of children’s charities,” Kirkpatrick said. “This is just another example of how giving the guy is. But I’ve known that for a long time.”