Idina Menzel and Denzel Washington flexed their box office muscle on Broadway last week, as Menzel topliner “If/Then” and Washington starrer “A Raisin in the Sun” each posted impressive tallies in their initial week on the boards.

The only new musical of the spring not based on a well-known film property, “If/Then” seems like one of the current Broadway slate’s toughest sells — but the tuner nonetheless pulled in a potent $909,159 in its first seven previews, outpacing more familiar titles including “Rocky” ($635,153) and “The Bridges of Madison County” ($476,005), both of which played full weeks of eight perfs each.

Multiple factors contribute to the show’s strong debut, not least of which is the star power of Menzel. The actress has long had a devoted and surprisingly broad legit following from her perfs in “Rent” and “Wicked,” and more recently has won fans thanks to her starring role in Disney animated hit “Frozen.” Her recent appearance on the Oscars to perform the pic’s centerpiece tune, “Let It Go” — along with John Travolta’s attention-getting mispronunciation of her name — gave her profile one more boost in recent days.

“If/Then,” pictured above in its tryout run in D.C., also benefits from the additional legit-avid cred of its creative team, Tom Kitt and Brian Yorkey, the duo whose last Broadway outing, “Next to Normal,” scored them the Pulitzer Prize. That pedigree, coupled with Menzel’s name on the marquee, managed to secure “If/Then” a spot in the week’s Top 10 ahead of both Carole King bio-tuner “Beautiful” ($847,672) and “Aladdin” ($826,491), although the latter played only six previews last week.

Meanwhile, “Raisin in the Sun” racked up $151,179 from just a single performance. Washington has already proven his B.O. might with the 2010 revival “Fences,” so it seems a sure bet that audience enthusiasm will remain at a fever pitch, pushing the revival into the upper echelons of the sales charts.

Among the other recent additions to the Broadway lineup, the previewing revival of “Les Miserables” ($964,004 for seven) continued to sell vigorously, drawing crowds with a well-known title that in the last few years has been rejuvenated by Susan Boyle and by the 2012 movie adaptation. Meanwhile, Bryan Cranston starrer “All the Way” ($736,790), which earned universal praise for Cranston (if not for the play itself) after its March 6 bow, managed to rise vs. the prior frame despite accommodating  heavily comped press performances and its opening night.

As the rolling schedule of academic spring breaks began in schools around the country, Broadway overall rose. The total cume climbed more than $2.75 million to $21.3 million for 28 shows on the boards, and attendance spiked by 20,000 to hit 223,002.

With “Rocky” heading toward its March 13 opening, activity on the Rialto will gain further momentum with the addition of “Bullets Over Broadway” and Toni Collette-Michael C. Hall starrer “The Realistic Joneses,” both of which begin previews this week.