We saw Mariah Carey and Glee star Matthew Morrison a couple of times this weekend as we were immersed in "Christmas in Washington."

As far as feel-good celebs and events, it doesn't get much better than this. ...

Saturday afternoon, we watched a glowing and pregnant Mariah and a "hot" Matthew both rehearse for the annual concert event at the National Building Museum.

Then, we actually bumped into both of them near the wardrobe area. (Ali, a fan of Glee, was speechless around "hot" Matthew. It was pretty funny.)

On Sunday, we saw them again at the main "Christmas in Washington" event, along with:

• President Barack Obama
• The First Family
• Annie Lennox
• Italian tenor Andrea Bocelli
• Ellen DeGeneres (the host of the event)
• Portia de Rossi (Ellen's wifey, who sat in the front row, beside the First Family)
• Miranda Cosgrove of "iCarly"

The event, which was also attended by several politicians and their families, was produced by TNT and benefited the Children's National Medical Center.

It airs Friday night on TNT.


PHOTOS:
Saturday's "Christmas in Washington" rehearsal

Mariah practices with the children's choir

The stage looked fab in daylight, too!

~ Ali Lewis contributed to this report