hair pants Hilary Duff purse ring jeans byron and traceyAnd it's no surprise -- the starlet's tresses are tended to by some of the best in the biz, Byron & Tracey!

Hilary flashed a smile in Beverly Hills yesterday, after celebrating her 23rd birthday the day before with Hil's mom and sister Haylie.

Hilary's hubby, Mike Comrie, is busy getting ready for the new NHL season, so I guess we won't be seeing too many his n' hers workout sessions again in the near future!