Katy Perry and John Mayer dating again? This will be the fourth time Katy Perry and John Mayer have kindled a relationship and their friends say this time it's love. The couple, who collaborated on the song "Who You Love," look like they are giving dating another chance.

On Saturday, the "Roar" singer and the blues guitarist were spotted on a romantic double date with Allison Williams and her fiancé Ricky Van Veen at the Chateau Marmont. Witnesses say Perry and Mayer looked like a couple in love. The musical pair held hands and kissed.

"They are in love. They missed each other," a Perry insider told People magazine.

Katy Perry and John Mayer have been dating on and off since 2012

"They never stopped talking and being friendly while they were broken up. They are really excited about being together right now and spending as much time as possible... they have spent almost every night together this week," an insider told told E! News.

"They seemed very comfortable together and kissed several times. It was a cold night and they held hands and John pulled her in close when she got cold," the source told E! News.

Us Weekly also reported on the double dated with the Girls star and her fiancé,.

But Radar Online is reporting that Perry's friends have been warning her about Mayer's track record.

"Although her friends have warned her to be careful, she is already ignoring all of the red flags. She is not listening to anyone and is going into this full force," an insider told Radar Online.

The magazine reports that John Mayer was jealous when Katy Perry started dating .

"It drove [John] crazy seeing her with Diplo. Katy is giving John another chance because she feels like there could be something there," the insider told Radar Online.

An insider told Radar "Katy is giving John another chance because she feels like there could be something there... John pursued Katy relentlessly because it drove him crazy seeing her with Diplo."