Christina Aguilera has spent a lot of time shooting down comparisons to Lady Gaga.

But perhaps this artist should have been promoting her summer tour instead.

Sources confirm that Aguilera's summer concerts in North America have been canceled, likely due to poor ticket sales, although the performer's reps are claiming otherwise (naturally). They say the tour has merely been "postponed" until 2011 because:

"The singer felt she needed more time to rehearse the show and with less than a month between the album release and tour date this wasn’t possible."

A true sign of whether Christina's comeback has already flopped will be when her album hits stores on June 8. If "Bionic" doesn't sell well, Aguilera may be forced to embrace her inner thespian.

She does make her feature film debut in November's Burlesque, after all.

Without a tour this summer, at least Christina can spent more time at home. Toddler son Max is a certified cutie.