Jessica Biel believes that Justin Timberlake didn't cheat on her

A source told PEOPLE: "He's charming and outgoing. And obviously he drank too much this time, but Jessica believes he didn't cheat on her. She will stand by him.

"They will work through this. It was good that he apologised publicly but obviously the real work he is doing is in private and hopefully this was just a bad drunken night of this type of behaviour.”

Justin - who has four-year-old son Silas with his wife - has spoken of his regret at such a "strong lapse in judgement" while under the influence of alcohol because he has embarrassed his family.

He said in a statement posted to on social media: "I stay away from gossip as much as I can, but for my family I feel it is important to address recent rumors that are hurting the people that I love.

"A few weeks ago I displayed a strong lapse in judgement - 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 (sic)."

Justin ended his statement by stressing he is still happy to be working on 'Palmer'.

He wrote: "I am incredibly proud to be working on Palmer. Looking forward to continuing to make this movie and excited for people to see it."

And the 'SexyBack' hitmaker and his wife are already taking steps to move on from the scandal.

A source said: "They are downplaying everything and trying to laugh it off as nothing. But it was definitely inappropriate and something that would make any wife uncomfortable. He had too much to drink and got carried away. Their marriage will survive.

"She is very good to him and he knows how lucky he is. He says it was not a big deal, they were all hanging out together and that's the end of the story."