Kellan Lutz Hercules The Grove Beverly Hills Extra Mario Lopez

We see why Miley likes this guy!

Kellan Lutz was gracious enough to show us his underwear on Thursday ... why? We don't know. Maybe he's promoting a new line of men's undergarments?

Whatever the case, Mr. Lutz looked hotter than ever, showing off his toned pecs in a tight waffle-T. The rumored-to-be boyfriend of Miley Cyrus hit the Grove to talk to Extra's Mario Lopez. Which makes us wonder ... who do YOU think if more pec-alicious -- Kellan or Mario?