Justin arrives with mom, leaves with Selena

• Young stars reportedly got into an argument over weekend
• Bieber was named artist of the year
• Gomez kept a low profile at the American Music Awards

Justin Bieber had a busy, crazy night at the American Music Awards.

After weekend reports that he and sweetie Selena Gomez met up in L.A. — only to get into an argument, Bieber walked the red carpet at Sunday's big music show with a safe date: his mother, Pattie Mallette. She even joined him on stage when he accepted the award for artist of the year, beating out Rihanna, Maroon 5, Katy Perry and Drake.

"I wanted to thank you for always believing in me," Bieber said, looking at Pattie, 38.

But when the show was over, E!'s Mark Malkin reports that multiple sources saw Bieber leave the Nokia Theatre hand-in-hand with Gomez (who was not officially at the awards).

And in this Tumblr photo, the two together are definitely together, Selena holding on to Justin's arm.

Jenny McCarthy, who was a presenter at the show, confirmed it on Twitter, writing: "My cub @justinbeiber brought his acceptable and beautifully aged beauty Selena to the AMA after party. Guess I'm back on the prowl. Rww!"

Earlier in the night, McCarthy tried to sink her cougar claws into Bieber. As she presented him with his second award, she kissed him on the neck. "Wow. I feel violated right now," he said, laughing.

As of 1 a.m., TMZ characterized the Justin-Selena relationship as "still single. ... at the moment."