The '99 Problems' rapper was spotted backstage "flirting" with the singer - who announced she was expecting her first child at the ceremony at Los Angeles' Nokia Theatre on Sunday (28.08.11) - and was by her side throughout the event to offer assistance.
A source said: "Jay was doting on her the whole time.
"He yelled, 'Mmm hmmm, Who's that sexy lady walking down here?' playing like he was flirting with her. It was so cute.
"He was really taking care of her, asking her how she feels and helping her walk. It was so sweet to see him like that."
The 29-year-old beauty - who married the 41-year-old hip-hop star in 2008 - was also being looked after by her mum, Tina Knowles, as she spent time backstage at the ceremony before she took to the stage to perform 'Love On Top'.
An insider added to Us Weekly magazine: "She was on top of everything - getting Beyonce everything she needed... Between Jay and her mom, she was totally taken care of. Her mom was getting her everything she needed."
Lady GaGa - who attended the ceremony dressed as her male alter-ego Jo Calderone - also made a fuss of Beyonce, visiting her dressing room a number of times to rub her stomach.
A source explained: "She kept coming over to rub Beyonce's belly and say hello. And the security guards thought she was a guy at first and wouldn't let her back! It was really funny."
Made in America Festival is an annual music event founded by rapper and businessman Jay-Z...
Somehow the people at Universal Pictures got it into their heads that easy-on-the-eyes, thin-on-talent Jessica...