A source told the publication that Biel "encouraged Justin to put out his statement on Instagram because she felt embarrassed by his actions and wanted him to take accountability".
In his apology, Timberlake admitted he had made a "strong lapse in judgment" when getting close to his co-star at a New Orleans bar.
In a statement released via Instagram on Thursday, the SexyBack singer apologised to his "amazing wife and family" for putting them through such an "embarrassing situation" – but insisted that nothing else had occurred between himself and Wainwright, news.com.au reports.
"I stay away from gossip as much as I can, but for my family I feel it is important to address recent rumours that are hurting the people I love," Timberlake wrote.
"A few weeks ago I displayed a strong lapse in judgment – but let me be clear – nothing happened between me and my co-star. I drank way too much that night and I regret my behaviour.
"I should have known better. This is not the example I want to set for my son. I apologise to my amazing wife and family for putting them through such an embarrassing situation, and I am focused on being the best husband and father I can be. This was not that.
"I am incredibly proud to be working on Palmer. Looking forward to continuing to make this movie and excited for people to see it."