We present a novel approach to model the nearby stars \alpha Cen A & B and Procyon A using asteroseismic and interferometric constraints .
Using the VINCI instrument installed at the VLT Interferometer ( VLTI ) , the angular diameters of the \alpha Centauri system were measured with a relative precision of 0.2 % and 0.6 % , respectively .
From these values , we derive linear radii of R [ A ] = 1.224 \pm 0.003 R _ { \odot } 
and R [ B ] = 0.863 \pm 0.005 R _ { \odot } .
These radii are in excellent agreement with the models of Thévenin et al .
( \citeyear thevenin02 ) , that use asteroseismic frequencies as constraints ( Bouchy & Carrier \citeyear bouchy01 ; Bouchy & Carrier \citeyear bouchy02 ) .
With the same instrument , we also measured the angular diameter of Procyon A .
Using the Hipparcos parallax , we obtain a linear radius of 2.048 \pm 0.025 R _ { \odot } .
We use this result together with spectroscopic and photometric constraints to model this star with the CESAM code .
We also computed the adiabatic oscillation spectrum of our model of Procyon A , giving a mean large frequency separation of \Delta \nu _ { 0 } = 54.8 \mu Hz , in agreement with the seismic observations by Martìc et al .
( \citeyear martic01 ) .
Our model favours a mass around 1.4 M _ { \odot } for Procyon A .