The only woman Justin Timberlake is spending time with romantically is his longtime girlfriend, Jessica Biel.

Despite rumors that he had been cheating on her with TV personality Olivia Munn during a weekend in September, a source tells our friends over @PEOPLE, "There is no truth to the reports. Olivia Munn is not that type of girl."

Last weekend, Timberlake, 29, was hanging out with Biel in a skybox on Sunday during the dramatic ending of the Justin Timberlake Shriners Hosptials for Children Open golf tournament at TPC Summerlin in Las Vegas. The actress also spent time with Timberlake's family, and was spotted backstage at his Saturday night benefit concert at the Planet Hollywood Resort and Casino, which featured a performance by Christina Aguilera.

After the show, the couple continued their night at Haze Nightclub, arriving hand-in-hand around 2 a.m.

"They were sitting in a private area of the club," a source tells our friends over @PEOPLE. "Most people didn't even know they were there. They were really affectionate and really seemed to be happy."

On Tuesday night, the pair stepped out for dinner at Fraiche in Culver City, Calif. Timberlake was also by his girlfriend's side on Monday night, supporting her at a screening of a short film she directed, which debuted at the Chateau Marmont.

Another source adds, "Justin and Jessica are doing fine."

Reps for Munn and Timberlake had no comment about their clients' personal lives.